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Full text of "Effective treatments of over and undercrossings for use by bicyclists, pedestrians, and the handicapped"

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FHWA 

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70-70 



lo. FHWA-RD-79-70 



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DEPARTMENT OF 
TRANSPORTATION 



3 



;tive treatments of over and 
:::.iRCROSSiNGS for use by bicyclists, 
pedestrians and the handicapped 



January 1981 
Final Report 





*MrES o* 



Document is available to the public through 
the National Technical Information Service, 
Springfield, Virginia 22161 



Prepared for 

FEDERAL highway administration 

Offices of Research & Development 
Environmental Division 
Washington, D.C 20590 



FOREWORD 



This report provides information on the feasibility of retrofitting existing 
over- and undercrossing facilities to accommodate the non-motorized 
travelers . 

Research in pedestrian and bicycle safety is included in the Federally 
Coordinated Program of Highway Research and Development as Task 3 of 
Project IE, "Safety of Pedestrians and Abutting Property Occupants." 
Mr. John C. Fegan is the Project Manager. 

One copy of this report is being distributed to each FHWA regional and 
division office. 



J- 




J Charles F. Scheffey 

Director, Office of Research 
Federal Highway Administration 



NOTICE 

This document is disseminated under the sponsorship of the Department 
of Transportation in the interest of information exchange. The 
United States Government assumes no liability for its contents or 
use thereof. The contents of this report reflect the views of the 
contractor, who is responsible for the accuracy of the data pre- 
sented herein. The contents do not necessarily reflect the official 
views or policy of the Department of Transportation. This report 
does not constitute a standard, specification, or regulation. 

The United States Government does not endorse products or manufacturers 
Trade or manufacturers' names appear herein only because they are 
considered essential to the object of this document. 






Technical Report Documentation Page 



T. Report No. 






FHWA-RD-79-70 



2. Government Accession No. 



3. Recipient's Catalog No. 



4. Title and Subtitle 

EFFECTIVE TREATMENTS OF OVER AND UNDERCROS SINGS FOR 
USE BY BICYCLISTS, PEDESTRIANS AND THE HANDICAPPED. 



5. Report Date 

January 1981 



6. Performing Organization Code 



7. Author's) 



8. Performing Organization Report No. 



C. De Leuw, Jr., F. Danielson, W. Kudlick, S. Swan 



9. Performing Organization Name and Address 

De Leuw, Cather & Company 

120 Howard Street 

San Francisco, CA. 94105 



10. Work Unit No. (TRAIS) 

FCP 31E3032 



11. Contract or Grant No. 

DOT-FH-11-9247 



12. Sponsoring Agency Name ond Address 

Offices of Research and Development 
Federal Highway Administration 
U.S. Department of Transportation 
Washington. D. C. 20590 



13. Type of Report and Period Covered 

Final Report 
March 1977 - May 1979 



14. Sponsoring Agency Code 



SrOsT" 



15. Supplementary Notes 

FHWA Contract Manager: Phebe D. Howell, HRS-41 

John C. Fegan, HRS-41 



16 v Abstract 

This study provides information about over and undercrossings directed toward planners 
designers and decision makers who are trying to best serve the needs of bicyclists, 
pedestrians and the handicapped, whether by means of constructing new facilities or by 
retrofitting improvements to existing structures. The study was designed to accomplis 
three basic objectives: 

1. Determine the feasibility of new and retrofit design modifications of over- 
and undercrossings for use by non-motorized travelers; 

2. Develop warrants for new and retrofit design modifications of crossings for 
these three user groups; and 

3. Develop design strategies for the accommodation of these three user groups on 
new and retrofit crossings. 

This report includes a review of the state of the art; a discussion of facility 
needs assessment procedures, including warrants and design selection criteria; the 
results of field evaluations of various over- and undercrossing facilities conducted 
by a team of engineers and a panel made up of members with various types of physical 
disabilities; and recommeded design treatments. Also, features for non-structural 
solutions and innovative or less traditional treatments, as well as prototypical 
design strategies for both new and retrofit facilities, and examples of desirable 
and undesirable design practices are given. 



17. Key Words 

Bicycle(s) 
Bicyclists 
Pedestrians 
Handicapped 



Undercrossings 
Overcrossings 



18. Distribution Statement 



No restrictions. This document is avail- 
able to the public through the National 
Technical Information Service, Springfield, 
Virginia 22161 



19. Security Clossif. (of this report) 

Unclassified 



20. Security Classif. (of this page) 

Unclassified 



21. No. of Pages 

225 



22. Price 



Form DOT F 1700.7 (8-72) 



Reproduction of completed page authorized 



TABLE OF CONTENTS 



Page 

TABLE OF CONTENTS iii 

1.0 INTRODUCTION AND SUMMARY 1 

1.1 Background 1 

1 .2 Study Purpose 1 

1.3 Organization of This Report 1 

1.4 Summary of Key Findings 2 

1.4.1 State of the Art Review 2 

1.4.2 Facility Needs Assessment 4 

1.4.3 Design Strategies and Considerations 5 

1.4.4 Handicap Considerations 7 

1.4.5 Cooperating Organizations 8 

2.0 STUDY METHODOLOGY AND APPROACH 9 

2.1 Introduction 9 

2.2 State of the Art Review 9 

2.2.1 Literature Review 9 

2.2.2 Review of Recent Experience 11 

2.3 Research and Development 12 
2.3-1 Needs Assessment and Design Selection Criteria 12 
2.3.2 Design Strategies 13 

2.4 Field Evaluations 13 

2.4.1 Site Selection 14 

2.4.2 Field Procedures 15 

3.0 STATE OF THE ART REVIEW 17 

3.1 Introduction 17 

3.2 Literature Review 17 

3.3 Case Study Compilation 18 

3.3.1 Case Study Information 18 

3.3.2 Conclusions About Current Decision-Making Procedures 19 
and Design Practices 

3.4 User Characteristics 21 

3.4.1 Pedestrian Characteristics 21 

3.4.2 Cyclists Characteristics 23 

3.4.3 Characteristics of the Handicapped Traveler 24 

3.5 Crossing Conditions 25 

3.5.1 Location Characteristics 27 

3.5.2 Structure 28 

3.5.3 Approach 29 

3.5.4 End Conditions 29 

3.6 Hazards and Impediments 29 

3.6.1 Pedestrian Facilities 29 

3.6.2 Bicycle Facilities 31 

3.6.3 Handicapped Facilities 32 

3.7 Design Standards and Approaches 33 

3.7.1 Design Standards 33 

3.7.2 Accommodating the Non-Motorized 33 



111 



TABLE OF CONTENTS (Continued) 



Page 



4.0 NEEDS ASSESSMENT 35 

4.1 Introduction 35 

4.2 Warrants 35 

4.2.1 Purpose of a Warrant 35 

4.2.2 The Need for Warrants 36 

4.2.3 Warrant Types 36 

4.2.4 Use of Warrants 37 

4.2.5 Current Warrant Systems 38 

4.3 Research Experience 45 

4.3.1 Palo Alto, California 45 

4.3.2 Sunnyvale, California 45 

4.3.3 Eugene, Oregon 45 

4.3.4 Hampton, New Hampshire 46 

4.3.5 Maryland 46 

4.3.6 Austin, Texas 46 

4.3.7 Summary and Conclusions 46 

4.4 Needs Assessment Process 47 

4.4.1 Identify Problem and Sites 49 

4.4.2 Data Gathering 49 

4.4.3 Examining Alternatives 51 

4.4.4 Mandatory Pre-Condi tions 52 

4.4.5 Reviewing Warrants and Criteria 53 

4.4.6 Establishing Priorities 55 

4.4.7 Implementation Action 55 

5.0 DESIGN SELECTION CRITERIA AND DESIGN CONCEPT 57 

5.1 Introduction 57 

5.2 Design Selection Criteria 57 

5.2.1 Non-Structural Versus Structural Solutions 57 

5.2.2 Over- or Undercrossing 58 

5.2.3 Exclusive or Shared Structure 58 

5.2.4 New Versus Retrofit Structure 60 

5.2.5 One-Sided Versus Two-Sided Non-Motorized Facilities 60 

5.2.6 Special Design Feature 60 

5.3 Design Concepts 62 

5.3.1 Crossing Classification Systems 62 

5.3.2 Derivation of the Prototypical Design Strategy 64 

5.3.3 Non-Structural Solutions 67 

5.3.4 Structural Solutions 67 

5.3.5 Innovative and Unusual Treatments 69 



IV 



TABLE OF CONTENTS (Continued) 



Page 

6.0 FIELD EVALUATIONS 70 

6.1 Introduction 70 

6.2 Comprehensive Evaluation Sites 70 

6.3 General Observations 71 

6.3.1 Deficiency in Signs, Signals and Markings 71 

6.3.2 Deficiency in Maintenance 73 

6.3.3 Deficiency in Design Features 74 

6. 4 General Findings 76 

6.4.1 User Counts 76 

6.4.2 Direction of Travel 77 

6.4.3 User Position 77 

6.4.4 Handicapped Features 77 

6.4.5 Travel Behavior 79 

6.4.6 Short Cut Routes 79 

6.4.7 Noise 0_ual ities 79 

6.4.8 Structural Stability 79 

6.4.9 Design Elements 80 
6.4.10Trip Generation 81 

6.5 Handicapped User Evaluation 84 

6.5.1 San Francisco Bay Area Sites 85 

6.5.2 Miami, Florida, Area Sites 85 

6.5.3 Summary of Findings 91 

6.6 Supplemental Field Investigations 95 

7.0 DESIGN APPROACHES AND STRATEGIES 100 

7.1 Introduction 100 

7.2 Design Considerations, Standards and Features 100 

7.2.1 Over- and Undercrossings as Systems 100 

7.2.2 Design Elements 100 

7.2.3 Designing for Multiple Users 105 

7.2.4 Designing for the Handicapped 106 

7.3 Design Strategies and Treatments 109 

7.3.1 Introduction 109 

7.3.2 New Projects-Generic Design Strategies 111 

7.3.3 Retrofit Projects-Generic Design Strategies 125 

7.3.4 End Conditions 125 

7.3.5 Non-Structural Solutions to Crossing Problems 140 

7.3.6 Design Innovation and New Techniques 148 

7.3.7 Improved Designer and User Understanding 159 

7.3.8 Handicapped Considerations 161 

7.3.9 Current Design Strategies - Adequate and Inadequate 164 

GLOSSARY 175 

REFERENCES 180 

V 



TABLE OF CONTENTS (Continued) 



Page 

APPENDIX A 186 
Pedestrian Facility Evaluation Variables 

APPENDIX B 187 

Case Study Summary and Identification Number 

APPENDIX C 190 
Design Selection Criteria Worksheets 

APPENDIX D I93 
Detailed Site Evaluation Descriptions 

Palo Alto, California 193 

Sunnyvale, California 196 

Eugene, Oregon 198 

Hampton, New Hampshire 208 

Route 183, Randolph Road, Maryland 208 

Austin, Texas 210 



VI 



LIST OF FIGURES 



Page 

1. Study Conceptual Approach 10 

2. Grade Crossing Elements 27 

3. Facility Need Assessment Process 48 

4. Crossing Classification System 63 

5. New Project Grade Separation Classification 65 

6. Retrofit Project Classification 66 

7. User Position on Pathway 78 

8. Trip Generation Characteristics - Field Evaluation Form 83 

9. Handicapped User Panel Evaluation Sites, California 87 

10. Handicapped User Panel Evaluation Sites, Florida 89 

11. Handicapped User Panel Evaluation Sites, Florida 90 

12. Selected Site Views 96 

13. Selected Site Views 97 

14. Selected Site Views 99 

15. New Project 1 - Four Lane Overcrossing Shared with 113 
Motor Vehicles 

16. New Project 2 - Four Lane Underpass Shared with Motor 115 
Vehicles 

17. New Project 3 - Bicycle and Pedestrian Overcrossings 117 

18. New Project 4 - Bicycle and Pedestrian Overcrossings 120 
Less than 100 Feet Long 

19. New Project 5 - Bicycle and Pedestrian Undercrossing 123 

20. Retrofit Project 1 - Cantilever Addition of Bicycle 127 
and Pedestrian Facilities to an Overcrossing 

21. Retrofit Project 2 - Expansion or Upgrading of 130 
Existing Bicycle and Pedestrian Facilities 

22. Retrofit Project 3 - Convert an Existing Over and 132 
Undercrossing to Exclusive Use of Bicyclists and 
Pedestrians 

23. Signing and Striping 1 42 

24. Warning Sign System - Bike Presence in Tunnel 143 

25. Crosswalk and Guide Signing 144 

26. Utilizing Alternative Travel Modes 147 

27. Unusual Facility Configurations 150 

28. Differential Sidewalk Settlement 152 

29. Sidewalk/Driveway Relationships 153 

30. Conceptual Rest Area Alternatives 155 

31. Railroad Flat Car Bridge 156 

32. Trai ler Truck Beds (Potential Bridge) 157 

33. James A. Hawkinson Pedestrian-Bicycle Bridge, Palo 195 
Alto, California 

34. Ahwanee Pedestrian Overcrossing of Route 101, 197 
Sunnyvale, California 

35. Undercrossing of the Southern Pacific Railroad, 200 
Eugene, Oregon 



vi 1 



LIST OF FIGURES (Continued) 



Page 



36. Retrofitted Ramp, Ferry Street Bridge, Eugene, Oregon 202 

37. Ferry Street Bridge, Eugene, Oregon 203 

38. Supplemental Inspection Sites, Eugene, Oregon 206 

39. Retrofitted Bridge, Hampton, New Hampshire 209 

40. Box Culvert Undercrossing, Maryland Route 1 83 211 

41. Fifth Street Bikeway, Austin, Texas 215 
hi. Sixth Street Bikeway, Austin, Texas 216 
^3. North-South Bikeway, Austin, Texas 217 



LIST OF TABLES 



Page 

1. Mobility Needs by Disability Type 26 

2. Typical Ramp Lengths for Overpasses and Underpasses 59 

3. Site Evaluation - Especially Good Features 72 
k. Site Evaluation - User Count Summary 76 

5. Site Evaluation - Bicycle and Pedestrian Trip Generators 82 

6. California Overcrossings Evaluated by Handicapped 86 
User Panel 

7. Florida Overcrossings Evaluated by Handicapped User 88 
Panel 

8. Design Guidelines for Geometric Elements 102 

9. Most Desirable Design Guidelines 107 

10. Radius of Curvature - Bicycles 108 

11. Stopping Sight Distances - Bicycles 108 

12. Design Guidelines for Prototypical Over and ]2h 
Undercrossings 

13. Current Design Strategies Adequate or Commendable 165 
\k. Inadequate or Undesirable Design Strategies 169 

15. Summary of Construction Cost - Palo Alto, California 7 94 
Bridge 

16. Estimated Construction Quantitites - Sunnyvale, 198 
Cal ifornia Bridge 

17. Preliminary Cost Estimates - Eugene, Oregon Bridge 2Qk 
Sidewalk Widening 

18. Construction Quantities - Eugene, Oregon Bicycle- 207 
Pedestrian Bridge 

19. Estimated Construction Quantities - Maryland Route 212 
183 Box Culvert 

20. Estimated Construction Quantities - Austin, Texas 2\k 
Bikeways 



Vlll 



CHAPTER 1 

INTRODUCTION AND SUMMARY 



1.1 BACKGROUND 

Communities are becoming increasingly concerned with the transporta- 
tion needs of bicyclists, pedestrians and the handicapped. Of particular 
interest is the inclusion of facilities for such travelers when design- 
ing new over- and undercrossings, and in retrofitting improvements to 
existing structures. In some instances, the over- or undercrossing 
facilities constitute a barrier in themselves, which affect the ability 
of certain non-motorized travelers from using the facility. While some 
general guidance for the design of new crossing structures for cyclists 
is already available, a need for additional information has become evi- 
dent. Consequently, in March 1977, the U.S. Department of Transporta- 
tion, Federal Highway Administration (FHWA) , contracted with De Leuw, 
Cather & Company to undertake this study. 



1.2 STUDY PURPOSE 

The study was designed to accomplish three basic objectives: 

1. Determine the feasibility of new and retrofit design modifica- 
tions of over- and undercrossings for use by non-motorized 
travelers; i.e., bicyclists, pedestrians and the handicapped. 

2. Develop warrants for new and retrofit design modifications of 
crossings for these three user groups. 

3. Develop design strategies for the accommodation of these three 
user groups on new and retrofit crossings. 

The results of the study are intended for the use of federal, state 
and local officials and technical staffs engaged in both the planning 
and engineering design of such facilities, interested user groups and 
political decision -makers responsible for funding and implementation. 

1.3 ORGANIZATION OF THIS REPORT 

The report constitutes the principal documentation of all research 
activity undertaken in connection with the study and the major findings, 
conclusions and recommendations arising out of that activity. As such, 
the greater portion of the report is organized in parallel to the work 
tasks carried out in the course of the study. Chapter 2 describes the 
methodology used and the approach followed; Chapter 3 reviews the state 
of the art and evaluates current practice with respect to treatments 
of over- and undercrossings for use by bicyclists, pedestrians and the 

1 



handicapped; Chapter k deals with the needs assessment activities, 
including the areas of warrants; Chapter 5 discusses design selection 
criteria and formulation of design concepts; Chapter 6 summarizes the 
findings of the field evaluations which were conducted as a part of 
this study; and Chapter 7 presents descriptions and graphic portrayal 
of design strategies and design treatments. References are listed at 
the end of the report, while glossary of terms and other material are 
contained in the Appendix. 

A summary of key findings, results and recommendations is presented 
below in the remainder of this chapter. 



1 .4 SUMMARY OF KEY FINDINGS 

Particularly noteworthy findings are outlined below, grouped as follows: 

• State of the Art Review 

• Facility Needs Assessment 

• Design Strategies and Considerations 

• Handicap Considerations 

1.4.1 State of the Art Review 

The state of the art phase of the study encompasses both a review of 
the published literature and a compilation of 72 over- and undercross ing 
case studies. These, supplemented by a variety of field evaluations and 
design reviews, provided the basis for establishing the feasibility of new 
and retrofit design modifications. 

• In general, it was found that there is very little literature dealing 
directly with the subject matter of this study, and that for the most 
part over- and undercrossings have been treated as special situations 
in planning for non-motorized travel. 

• From the work carried out to date on case history studies, it is clear 
that there exists a very large number of applications throughout the 
country, but very few of them are documented. This may be because 
over- and undercrossing treatments have formed an incidental part of 
some larger project, or because no need for documentation beyond that 
needed for applications for funding and construction has been perceived. 

• As a general rule, each situation has, in the past, been evaluated 
individually. Where widely circulated sources have been used to aid 
evaluations, findings and recommendations have often been used 
without critical assessment. 



Many states have made provisions for customarily including facilities 
for non-motorized travel in plans for new or retrofitted under- and 
overpasses. 

When a decision is made by a state or local agency to construct 
facilities for bicyclists or pedestrians, usually at least one of the 
five following project "actuators" is present: 

A strong lobby representing bicycle riders. 

A developed state or local bikeway plan. 

Particular adjacent land users: 

schools 

parks and other recreational facilities 

residential development 

Recent accident and injury to a bicyclist or pedestrian. 

Sidewalks and/or a bikeway exist on approach roads to a 
planned structure. 

Cost is the most common reason why facilities for non-motorized travel 
are not provided. 

Until recently, it was rare to find provisions made with the handi- 
capped in mind on over- and undercross ing facilities. 

Retrofitting of motor vehicle overpasses or underpasses to accommo- 
date bicycle and pedestrian travel is not common. In instances 
where the retrofit involves structural modifications, general up- 
grading and repairs to the entire structure are usually undertaken 
concurrently. The most common retrofits are to bridges or other 
overcrossings, rather than undercrossings. 

Data was gathered for hi new projects and 25 retrofit projects from 16 
states around the United States. Of the k7 new projects case studies, 
39 were overcrossings and 8 were undercrossings, while 2k of the 
retrofit projects were overcrossings and only one was an undercross- 
ing. 

Field evaluations took the form of comprehensive evaluations at six 
selected sites. Visits to seven locations where the reactions of a 
panel made up of persons with a variety of physical disabilities were 
obtained. About 200 less formal investigations were conducted with 
respeet £©-one er^mere design or operational features. 

The primary products of the field evaluations were tabulations of 
especially good design features and observed deficiencies. The 
latter were grouped as follows: 



Signs, Signals and Markings - Maintenance - Design Features, and 
General Considerations 

• Types of barriers (subdivided into absolute obstacles and disincentive 
obstacles) and a variety of hazards and impediments to use of over- 
and undercrossings applicable to each of the user groups were also 
identified in the course of the study. 

].k.2 Facility Needs Assessment 

A variety of approaches are possible in deciding whether or not 
over- and undercrossings are needed. Based on the findings of this 
study, experience to date indicates that warranting procedures appear 
to facilitate decision-making and enhance reliability of results. 

• There is little doubt that an organized review of available informa- 
tion and a structured, systematic approach to rational decision-making 
is to be preferred, since it is most likely to produce credible, 
unbiased assessments. A logical framework for project analysis is 
presented in the report which includes the use of both warrants and 
design selection criteria. 

• The study found that a variety of different warrants are currently in 
use, either singly or in combination. These include: economic, 
system, threshold and point warrants. In addition, the roles of 
established policies and political prerogative (or community preference) 
should be explicitly recognized in the need assessment process. 

• A procedure which combines all, or elements of all, of these areas 
appears to be the most reasonable method for establishing the relative 
need for bicycle and pedestrian facilities on over- and undercrossings. 

• Design selection criteria help resolve such questions as: non-struc- 
tural versus structual solutions; overcrossing versus undercrossing; 
exclusive use or structures shared with motor vehicles; new facility 
versus retrofitted structure; and need for special features. 

« The needs assessment procedure should be uniformly applied without 
bias. It cannot, however, be followed blindly and must be combined 
with sound judgement based on experience. Similarly, it must be 
flexible enough to allow proper consideration of special circum- 
stances and conditions at a given site. 

• Establishing the degree to which warrants are satisfied should not be 
so cumbersome or require data so difficult to obtain that their use is 
discouraged. Similarly, the degree of precision of data and evalua- 
tion factors should not be in excess of their likely impact on the 
conclusions reached. 

• Based upon the research, it is our conclusion that there is no 
single formula or warrant which aggregates the individual criteria 
to give a "Build-No-Build" decision. 



• Adoption by a jurisdiction of specific policies addressing the needs 
of pedestrians, bicyclists and the handicapped, and the provisions 
for meeting those needs, can greatly simplify and expedite decision- 
making. 

1.4.3 Design Strategies and Considerations 

Major portions of this report deal with such areas as: general design 
considerations, standards and features; prototypical design strategies for 
five different types of new projects and three kinds of retrofit projects 
covering commonly encountered situations; discussions of non-structural as 
well as structural solutions and some potentially applicable innovative 
techniques. 



Many characteristics of non-motorized facilities are determined 
depending upon whether the primary purpose of the crossing is 
to serve motor vehicles, bicycles and pedestrians, or utilities. 



Planning, conceptual design and construction activities for such 
projects, therefore, should generally be predicated on concurrently 
meeting the combined requirements of bicyclists, pedestrian and the 
handicapped, as well as the needs of motor vehicle operators. 

Currently, maximum or minimum allowable design standards are often 
applied in practice, whereas use of desi rable design standards would 
be preferrable. (There is almost no conflict in design standards for 
bicyclists, pedestrian and the handicapped if the most desirable 
standards are used instead of maxima or minima.) In fact, inclusion 
of desirable features for one group of non-motorized travellers 
usually enhances travel for the others as well. 

To function smoothly as a part of the transportation network, over- and 
undercrossing design must be continuous with the existing facilities, 
as well as compatible with future plans. 

Non-structural solutions to crossing problems should receive primary 
consideration and be thoroughly evaluated as an alternative or 
supplement to a structural solution. Non-structural solutions can be 
grouped under five headings; Traffic Control Strategies, Alternative 
Routes, Alternatives Travel Modes, New Technologies and Land Use 
Planning. 

The discussion of design elements includes: geometries, details, 
special features and construction materials. Suggested design 
standards and treatments are described. 



Generic or prototypical design strategies in the form of detailed 
graphical illustrations and key design notes are presented for five of 
the most basic situations likely to be encountered: 

Overcrossing Shared with Motor Vehicles 
Underpass Shared with Motor Vehicles 
Long Bicycle and Pedestrian Bridge 
Short Bicycle and Pedestrian Bridge 
Bicycle and Pedestrian Undercrossing 

Similarly, basic retrofit design strategies are presented, as follows: 

Cantilever Addition of Non-Motorized Facilities to an Overcrossing 
Expansion or Upgrading of Existing Non-Motorized Facilities 
Conversion of an Existing Over- or Undercrossing to Exclusive 
Use by Bicyclists and Pedestrians. 

Since the three grade crossings components (ends, approaches and 
structures) function together as a crossing system, end conditions 
must also be considered in the design process. The report, therefore, 
contains a section describing potent ial problems appl i cable to five basic 
kinds of end conditions which can be combined with the treatments of 
approaches and structures discussed elsewhere in the report. 

The results of this research study indicate that there is no imminent 
technological breakthroughs that will drastically change the develop- 
ment of non-motorized facilities on over- and undercross ings. How- 
ever, there are a number of modifications or enhancements of existing 
methodology and procedures which are innovative and which may have 
application to specific problems. 

Unintentional exclusion of some non-motorized users has occurred in 
certain situations because maximum and minimum standards were incor- 
rectly uti 1 ized. 

The design deficiencies which were observed fell into three general 
areas: signs, signals and markings; maintenance; and design features. 
The major findings in each of these areas are summarized below. 

- By far the most common deficiency of the sites visited pertained 
to a general lack of guide and directional signing facilitating 
travel by bicyclists and pedestrians. The next most common 
deficiency related to signing was lack of proper horizontal and/ 
or vertical clearance between the sign or sign post and the path- 
way edge. 

Periodic maintenance is necessary to maintain the effectiveness 
and attractiveness of even the best design. Proper design can 
minimize the magnitude of maintenance effort and costs required. 
Most maintenance deficiencies observed at the site evaluation 
locations were related to debris or vegetation on the pathway. 



- Typical features identified as deficient during the site evalua- 
tions involved elements which were incomplete and fall into 
three categories: Alignment and Clearances; Sight Distance and 
Pavement Quality; and Appurtenances. Specific examples in each 
area are cited in the body of this report. 

• The findings of this study indicate that the planning, design and 
operation of non-motorized facilities on over- and undercrossings 
can be considerably enhanced if technical personnel and facility 
users achieve a better understanding of the subject matter and 
several means of improved education and communications are suggest- 
ed in the report. 

• Examples of both adequate and inadequate crossing treatments and 
designs were identified as a part of this study. These are describ- 
ed and, for the deficient treatments, corrective measures are 
suggested. Material is grouped as follows: sidewalks; railings 
and fences; structure; traffic control; and maintenance. 

1.4. 2f Handicap Considerations 



In view of the importance of this topic in terms of both social 
concern and potential impact on the limited funds available for main- 
taining, replacing and/or improving existing over- and undercrossings 
and statutory requirements under Title 23 of the Highway Act to ensure 
that certain federally assisted facilities are usable by handicapped 
persons, some key study results in this area are summarized below. 

• The handicapped are a heterogeneous group with varied mobility 
limitations and needs. Persons with apparently similar medical 
conditions are likely to vary in their physical stamina and will- 
ingness to negotiate level changes. 

• Many handicapped persons are able to use facilities designed for 
bicycles or pedestrians with little or no modification. Other 
handicapped persons would require special features such as ramps, 
rest areas or elevators. Finally, there are some persons who 
would not be able to use the over- or undercrossing regardless of 
the improvements provided. 

• Considerable attention has been focused in the past on the costs 
associated with accommodating the handicapped, particularly on 
ramp grade restrictions which increase their length and conse- 
quently their cost. Designers should realize, however, that they 
can greatly improve access for the handicapped at little cost by 
modifying some design details. Sidewalk cross slopes, curb widths, 
handrail types and configurations and pavement textures are all 
examples of elements of an over- or undercrossing that could be 
made more amenable through virtually zero cost alternations. 



• A general conclusion with regard to over- and undercrossing 
situations is that areas rather than just facilities should be 
made accessible so that continuous routes are available for 
non-motorized travelers. 

• Priorities for implementation of improvements on existing facilities 
to enhance handicapped accessibility should be based upon extent 

of need and anticipated use by the handicapped. 

• The method of using handicapped panelists to conduct on-site 
evaluations and /or be an advisory group was successful in this 
study, and can be a useful technique for local and state officials 
to use in the planning, design and decision-making process or 
retrofit construction of over- and undercrossings. 

1.A.5 Cooperating Organizations 

Numerous cooperating organizations and persons contributed their 
efforts, ideas, and data to this study. 

Mr. Hale Zukas and Eric Dibner of the Center for Independent Living, 
Inc., Berkeley, California, were participants from the outset of the 
study. They and their associates provided extensive knowledge of, and 
direct experience with, the needs of the physically handicapped traveler. 
Contributions were also made by volunteers from a number of organizations 
in Florida who served on the facilities evaluation panel. 

Many federal, state and local agency staff members, private practi- 
tioners, manufacturers, academics and other individuals supplied data, 
reports, drawings and other material and answered questions concerning 
individuals from agencies in the states of Alaska, California, Florida, 
Maryland, New Hampshire, North Dakota, Ohio, Texas, the Commonwealth 
of Virginia and the cities of Palo Alto and Sunnydale, California. 



8 



CHAPTER 2 

STUDY METHODOLOGY AND APPROACH 



2.1 INTRODUCTION 

This study extended over approximately a two year period and 
included the following activities: 

• State of the Art Review 

• Research and Development 

• Site Evaluations 

• Final Documentation 

Figure 1 on the following page illustrates the conceptual 
approach followed in conducting the study. 

The site evaluation activity was carried out: a formal, 
structural in-depth study of facilities at six selected locations 
(including a pilot project designed to test and improve evaluation 
procedures); evaluations of facility treatments for the handicapped 
conducted with the aid of a panel made up of persons with various 
types of disabilities; and less formal, less exhaustive evaluations 
made by study team members at numerous sites throughout the life of 
the project to either check on a limited number of design or opera- 
tional features or to generally add background material and photo- 
graphs to the study's data base. 

The remainder of this chapter contains an expanded description 
of the study methodology and approach utilized in carrying out the 
major activities in Figure 1. 



2.2 STATE OF THE ART REVIEW 

The state of the art review represents an analysis of the rele- 
vant literature in readily available published form, and recent 
experiences in the planning, design, and construction of crossing 
facilities and facility treatments to serve non-motorized travelers, 

2.2.1 Literature Review 

The literature review (1) was undertaken to not only provide 
basic resource data needed for this study, but also to develop an 
information source for practitioners in various aspects of the 
study topic. 



r 



=0 



STATE OF THE ART REVIEW 



LITERATURE REVIEW 



"> 



EXISTING HAZARDS 
AND IMPEDIMENTS 



CURRENT DESIGN 
PRACTICES 



DEFINE "STATE OF THE ART" 
WARRANTS AND SELECTION 
CRITERIA FOR DETERMINING 
FACILITIES NEEDS 



j5k_ 



EVALUATE CURRENT DESIGN 
STRATEGIES, IDENTIFY 
USEFULL DESIGNS AND 
DESIGN PITFALLS 



J&L. 



PUBLIC DOCUMENT: 
Literature Review 



r 



">v 



SITE EVALUATIONS 



CASE STUDY 

5 APPLICATIONS 



r^ 



REVISE DESIGN 
STRATEGIES 



~> 



MODIFY NEEDS 

ASSESSMENT 

PROCEDURES 



4> 



REVISE DESIGN 

SELECTION 

CRITERIA 



RESEARCH AND DEVELOPMENT 



DEVISE AND ASSESS 
NEW STRATEGIES, 
CRITERIA AND 
ANALYTIC PROCEDURES 



r> 



IMPROVED DESIGN 
STRATEGIES 



UPDATED NEEDS 

ASSESSMENT 

PROCEDURES 



4 



UPDATED DESIGN 

SELECTION 

CRITERIA 



4 



FINAL DOCUMENTATION 



PREPARE 
FINAL REPORTS 



PUBLIC DOCUMENT: 
Final Report 



Figure 1. STUDY CONCEPTUAL APPROACH 



10 



Several different techniques were used to insure that the most 
pertinent materials would be collected and reviewed. First, a list 
of key topics and relevant issues was prepared. Then, bibliographies 
were gathered and scanned to find sources addressing the listed key 
topics and issues. Major libraries and reference services were also 
contacted and asked to provide lists of applicable references. Con- 
tacts included the Highway Research Information Services, the Trans- 
portation Research Information Service, the National Technical 
Information Service, Northwestern University, Harvard, and MIT 
libraries, the Institute for Transportation Studies, University of 
California, UMTA abstracts, the Engineering Index, and the De Leuw, 
Cather and Center for Independent Living libraries. 

In addition, major contributors to research in the field in the 
United States and elsewhere and state and local practioners were 
contacted and asked to recommend literature sources addressing key 
aspects of the study problem. An initial review of gathered literature 
also provided a source for additional works. Finally, documentation 
of facility planning and design experience was collected from local 
and state agencies and De Leuw, Cather work files. This information 
was used to illustrate current practices in the field. 

2.2.2 Review of Recent Experience 

In order to ascertain the current design practices with respect 
to facilities for non-motorized travellers on over- and undercrossings, 
and to understand the rationale for developing facilities for the 
bicyclists, pedestrian and handicapped on particular structures, an 
extensive data gathering inquiry was undertaken. Building upon exist- 
ing study team contacts at the federal, state and local levels 
and the leads developed in the course of preparing the literature 
review, requests for information were made of state transportation 
departments (or their equivalents) in each of the 50 states, Puerto 
Rico and the District of Columbia. They were asked to supply descrip- 
tions of over- and undercrossing structures they had designed, with 
particular emphasis on those incorporating new or retrofitted facili- 
ties for bicycles and pedestrians. In addition, they were asked for 
referrals to jurisdictions within their area (cities, counties or 
other agencies) that might have experience with such facilities. 

The initial responses varied. Some agencies replied enthusias- 
tically and sent fairly complete project descriptions, drawings and 
cost information; others stated that they had had little relevant 
experience. Follow-up inquiries were then made as appropriate to 
elicit specific additional information about the projects mentioned 
and to explore the experiences of the cities, counties and other 
jurisdictions to which reference had been made. The material and 
data obtained was then combined with similar information already 
available in De Leuw, Cather files and that received from other 
sources. The resulting compilation, which was updated as material 

11 



continued to be received throughout the life of the study, was suffi- 
cient to draw appropriate conclusions about current design practices 
and standards and the dec is ion -making process with respect to pro- 
viding facilities for bicyclists and pedestrians and constituted a 
most valuable study resource. 



2.3 RESEARCH AND DEVELOPMENT 

The major activities undertaken in this phase of the study were 
the continuing work on facility needs assessment (or justification); 
assembly and analysis of design selection criteria; preparation of 
general design strategies and other potential solutions to meeting 
the needs of non-motorized travellers and review of promising design 
strategies with an expert panel. 

2.3.1 Needs Assessment and Design Selection Criteria 

The concept of warrants, is widely used within the needs assess- 
ment process as one of the techniques to assess the justification 
for providing a facility or other form of improvement. Warrants 
are measures of need which serve as guidelines in the decision-making 
process used in determining whether or not to do something. Design 
selection criteria, on the other hand, are guidelines for the next 
step; once it is decided that an improvement is justified, design 
selection criteria are guidelines which can assist in determining 
what specific type of facility or improvement best satisfies the 
needs. 

Development of a needs assessment procedure and design selection 
criteria involved gathering and analyzing material primarily drawn 
from the literature and state of the art reviews. A recommended 
needs assessment process was developed from this analysis and ulti- 
mately modified based upon experience gained from the site evalua- 
tions. 

The design selection criteria investigation dealt with decision- 
making with respect to choices in such areas as: 

• Non-structural versus structural solutions 

• Over- or undercrossing 

• Exclusive use or structure shared with motor vehicles 

• New versus retrofitted structures 

• Facilities on one or both sides of structures 

• Need for special features 

Work sheets were developed to assist in the documentation of the 
design selection analysis and are shown in the appendix. These were 
evaluated and refined by field testing at two locations in Calif- 
ornia. 

12 



2.3.2 Design Strategies 

The primary emphasis of this portion of the Research and Devel- 
opment phase was on seeking to improve current design practices and 
techniques. It included: completion of the gathering of decision- 
making, design, construction and cost data initiated during the 
state of the art review; preparation of design classification systems; 
analysis of design types to determine various generic design strat- 
egies; conduct of a Design Innovation Workshop with an expert panel 
consisting of senior personnel from De Leuw, Cather's structural, 
civil engineering, traffic and transportation planning departments 
— along with representatives from the Federal Highway Administration 
and the handicapped community. 

A number of different sources were utilized in the carrying out 
of the design strategies task. Principal among these were: 

• Published and unpublished literature, including design manuals, 
standards and guidelines for bicycle, pedestrian and handi- 
capped facilities from the American Association of State High- 
way and Transportation Officials and various State transpor- 
tation agencies, articles on construction and design tech- 
niques, and material use. 

• Conversations with designers of bicycle and pedestrian facil- 
ities and over- and undercrossings in a number of cities and 
states, and within De Leuw, Cather & Company. 

• The Design Innovation Workshop conducted on July 14, 1978, 
and the resulting notes and materials. 

The product of this phase of the study included initial defini- 
tions of: general design consideration; desirable standards and 
features of over- and undercrossing design elements; project classi- 
fication systems; eight prototypical new structure design strategies; 
six prototypical retrofit design strategies; end condition treat- 
ments; non-structural solutions; and design innovations and new 
techniques. 



2.4 FIELD EVALUATIONS 

The basic purpose of the site investigations carried out in the 
course of this study was to evaluate some of the promising new designs, 
design modifications and non-structural solutions previously identi- 
fied among the recorded 72 case study examples of current practice 
cited earlier (5). As mentioned above, the field work took the form 
of comprehensive evaluations at six selected sites, as well as visits 
to three locations in California and four in Florida where the react- 
ions of a panel made up of persons with different physical disabili- 
ties were obtained, and about 200 structures were visited and less 
formally inspected by team members throughout the duration of the 
study. 

13 



2.4. 1 Site Selection 

The initial step in selecting sites for field evaluation was 
to summarize the 72 case studies documented during the development 
of the State of the Art and Research and Development project phases. 
Information provided for each of the 72 sites included location, 
whether it was a new or retrofitted treatment; estimated order of 
magnitude of usage (high, medium, low) for motor vehicles, bikes, 
pedestrians and the handicapped; land use, whether urban or rural; 
an indication of whether the site was an especially innovative 
treatment and comments regarding basic design features. Criteria 
were established for site selection for comprehensive evaluations, 
as follows: 

• Innovative design features preferred 

• A mixture of new and retrofit designs required 

• Examples of both over- and undercrossing projects required 

• Sponsoring state and local agencies that had ongoing pro- 
grams for meeting the needs of bicyclists, pedestrians, and 
the handicapped preferred 

• A broad geographic distribution preferred 

Review of the material gathered indicated a number of potential 
sites located in the eastern, central and western United States. 
The three locations were: 

Palo Alto, California . An exclusive bicycle and pedestrian 
bridge with an approach canti levered along a drainage canal was 
selected as the site of the pilot study carried out to test and re- 
fine the site evaluation procedures. 

Sunnyvale, California . A new exclusive pedestrian and bicycle 
overcrossing of a busy freeway at this location was chosen as a repre- 
sentative example of a facility with the latest treatments intended 
to facilitate use by the handicapped. 

Eugene, Oregon . Two structures were evaluated in detail in 
Eugene, Oregon. One location combines a bicycle and pedestrian under- 
crossing of the Southern Pacific Railroad with a nearby bicycle and 
pedestrian bridge over the Willamette River. The second facility is 
a retrofitted direct ramp connection for bicyclists and pedestrians 
only, leading from the sidewalk along one side of a four-lane highway 
bridge to a park and riverside trail system. 

Designation of the remaining three sites chosen for in-depth 
evaluation took place after the conclusion of the July 1978 Design 
Innovation Workshop conducted as a part of the study. 



\k 



Hampton , New Hampsh i re . A retrofitted bicycle and pedestrian 
faci 1 ity canti levered from a highway bridge over a railroad was 
analyzed at this location. 

Route 183, Randolph Road, Maryland . This site was chosen for 
its modified box culvert featuring an elevated pathway capable of 
use during most of the year as an underpass, except when it becomes 
innundated during periods of high water. 

Austin, Texas . Special off-street facilities have been con- 
structed to accommodate bicycle and pedestrian travel through a 
complex interchange made up of one-way streets and ramps. 

Handicapped User Evaluation Sites . The seven sites for the field 
evaluation of facilities for the handicapped were chosen after dis- 
cussions with a panel of disabled persons with varied disabilities. 
Observation sites were selected in the San Francisco Bay and Miami, 
Florida areas to provide for a variety of recent designs of crossings 
with and without special provisions for the handicapped. Further, 
the sites were chosen so as to encompass a variety of situations 
likely to be commonly encountered by handicapped users (6, 7). 

2. A. 2 Field Procedures 

Prior to conducting the site evaluations, various procedures were 
evaluated during the pilot study to assure that the field reviews 
would produce the maximum amount of usable data. Forms were developed 
to assist in data retrieval. The study and observation techniques 
used were as follows: 

• General assessment of the facility was made independently by 
two engineers. 

• Measurements were taken of various elements, such as grades, 
slopes, etc. 

• Identification was made of features that might be critical 
to non-motorized travel. 

• Volume of users, by type and age, was noted for selected 
periods. 

• Observations were made of user travel behavior. 

• User position on pathway and extent of handrail usage were 
noted. 

• Photographs were taken and their location recorded. 



15 



Local designers and technical staff knowledgeable about the 
specific study site were also interviewed in person by the study team. 
The results of these conversations added depth to the knowledge of 
the site gained through the field evaluation. This was especially 
true in understanding the decision-making and planning process from 
the conception of the project through construction and operation. 

The field team was made up of a civil engineer with a running 
background and a traffic engineer/transportation planner who is a 
daily bicycle rider, thus providing a variety of user and evaluator 
perspectives. Additional personnel were assigned to the field team 
to assist with volume counts. 

Handicapped persons participated in the evaluation of seven 
sites. In each case they traversed the facility, its approaches and 
end conditions and thereby became familiar with the system as well 
as individual components. A set of choice responses and open-ended 
questions about the experience were then administered by study staff. 
This was followed by a more general discussion about the site among 
panelists and project staff. At each location, photographs were 
taken to illustrate major findings. 

Informal site visits usually consisted of general observation 
and frequently included the taking of photographs. At times, some 
measurements of specific features of interest were recorded and 
follow-up discussions with local officials were held either in person 
or by telephone. This material was then included as part of the 
study's information resources. 



16 



CHAPTER 3 

STATE OF THE ART REVIEW 

3.1 INTRODUCTION 

The previous chapter described how the review of readily avail- 
able published literature and recent experiences in the planning, 
design and construction of crossing facilities to serve non-motorized 
travelers was carried out to provide insight into current practice. 
This chapter presents the highlights of the results of that activity. 
Some general aspects of the literature review and case study compila- 
tion are first discussed, followed by more specific details concern- 
ing the State of the Art in such area as: 

• User Characteristics 

• Crossing Conditions 

• Hazards and Impediments 

• Design Standards and Approaches 



3.2 LITERATURE REVIEW 

In general, it was found that there is very little literature 
dealing directly with the subject matter of this study, and that for 
the most part crossings have been treated as special situations in 
planning for non-motorized travel. 

From the work carried out on case history studies, it is clear 
that there exists a very large number of applications throughout 
the country, but very few of them are documented. This may be because 
over- and undercrossing treatments have formed an incidental part of 
some larger project, or because no need for documentation beyond that 
needed for applications for funding and construction has been per- 
ceived. 

In addition to this final report, the 3^1 documents listed in 
the Annotated Bibliography section of the Literature Review Report(l) 
constitute a logical starting point for those seeking information on 
the subject topic of this study. For ease of access, the bibliography 
is subdivided into the sections listed below, plus a listing of other 
bibliographies and general references. 

• Travel Behavior and Needs of Non-Motorized Groups 

• Typical Crossing Situations 

• Crossing Hazards and Impediments 

• Needs Assessment Practices 

• Design Standards 

• Structural Treatments 



17 



• Non-Structural Solutions 

• Case Histories 

• Annotated Bibliography 

Each of these sections (except the Annotated Bibliography) pre- 
sents and appraises the major findings of the literature review. 
For each topic, analysis of references related to pedestrians is pre- 
sented first and then followed by a review of works pertaining to 
cyclists and the handicapped. 



3.3 CASE STUDY COMPILATION 

As stated in Chapter 2 earlier, the methodology used to gather 
the data for the 72 Case Studies incl uded contactswith State Trans- 
portation Departments (or their equivalent) in the 50 states, Puerto 
Rico and the District of Columbia. A number of cities and counties 
and other agencies were also contacted. Data received from all 
sources, together with information already in De Leuw, Cather files, 
were utilized as a base from which to draw conclusions about current 
design practices and standards and the decision-making process with 
respect to bicycle and pedestrian facilities associated with grade 
separations. The following section focuses on the kinds of informa- 
tion gathered, and the general conclusions that were derived. 

3-3-1 Case Study Information 

The kinds of information requested from the various agencies that 
responded to the initial inquiries was mul tifaceted. Desired data 
included the following: 

• A short account of what initiated the installation of the 
facilities — a brief project history. 

• The construction cost for the total project. (An engineer's 
estimate or unit bid sheet was desired.) 

• An estimate of the construction cost associated with accommo- 
dating bicyclists, pedestrians, and the handicapped. 

• The construction duration. 

• Available basic engineering drawings, such as a plan view of 
the structure, including approach and end treatments, and a 
typical cross-section of the structure itself. 



10 



Ultimately, data was gathered for k~l new projects and 25 retrofit 
projects from 16 states around the United States. Of the k"I new pro- 
jects case studies, 39 were overcrossings and 8 were undercrossings, 
while 2k of the retrofit projects were overcrossings and only one was 
an undercrossing. The case study information was supplied for the 
most part by those state or local agencies throughout the country 
who were most active in planning and construction of bicyclist, pedes- 
trian and handicapped facilities. The actual case study information 
received, other written replies from various agencies, plus telephone 
conversations and face-to-face discussions with designers and planners, 
allowed the formulation of some conclusions about current decision- 
making procedures and design practices. It is noteworthy, however, 
that many of the state transportation agencies responded that they had 
had little experience with the design and construction of facilities 
for the non-motorized traveler. 

3.3.2 Conclusions About Current Decision-Making 
Procedures and Design Practices 

• Many states have made provisions for customarily including 
facilities for non-motorized travel in plans for new or retro- 
fitted motor vehicle under- and overpasses. Usually, to assure 
consideration, requests for the accommodation of non-motorized 
travel must be made by an interested government agency or by 

a citizen's lobby. Thus, decision-making occurs discretely, 
structure by structure, rather than in a comprehensive and 
planned manner. 

• A comparison of rural and urban policies with respect to non- 
motorized travel provides an interesting contrast. In rural 
areas, no special provisions generally are made for non- 
motorized travel. The common clearance or shoulder widths of 
k-d feet (1.2-1.8M) on highway bridges, for example, is con- 
sidered sufficient for the use of the occasional bicyclist or 
pedestrian. 

• Near Metropolitan areas, provisions for pedestrians and bicycl- 
ists are more common in projects undertaken by both state and 
local agencies. 

• Smaller cities where a college or university exerts a signifi- 
cant influence in the community often are very committed to 
providing special facilities for pedestrians and bicyclists. 
Three notable examples are Davis, California; Eugene, Oregon and 
Austin, Texas. 

• When a decision is made by a state or local agency to construct 
facilities for bicyclists or pedestrians, usually at least one 
of the five following project "actuators" is present" 



19 



- A strong lobby representing bicycle riders. 

- A developed state or local bikeway plan. 

Particular adjacent land uses: 

schools 
— parks and other recreational facilities 

residential development 

Recent accident and injury to a bicyclist or pedestrian. 

Sidewalks and/or a bikeway exist on approach roads to a 
planned structure. 

Cost is the most common reason why facilities for non-motorized 
travel are not provided. A combination bicycle and pedestrian 
path on only one side of a structure whose main function is the 
movement of motor vehicles can increase construction costs from 
5 to 20 percent. A bridge solely for bicycle and pedestrian use 
with a clear deck width of 8 feet (2.4 M) could cost $30,000- 
$300,000 for lengths of 50 to 500 feet (15.2-152 M) . Since grade 
separated structures for bicycle and pedestrian facilities are 
considered luxury items by most government agencies, the costs 
associated with accommodating these activities tend to be heavily 
scrutinized. 

Until recently, it was rare to find provisions made with the 
handicapped in mind on over- and undercrossing facilities. 
Attention to such features has been focused on accommodating 
the handicapped only where receiving federal or state funds 
is contingent upon compliance with certain standards, or where 
a particularly effective organization of handicapped persons 
has been successful in alerting decision-makers and designers 
to the problem so that accessibility could be improved for all 
users. 

Attention has been focused on the cost associated with accommo- 
dating handicapped persons, particularly on the question of 
making grades and ramps less steep, thus increasing their length. 
However, some attention to design details such as approach 
sidewalk cross slopes, handrail types and configurations, and 
the texture of paved surfaces are all examples of elements that 
could be made more amenable to all users, including the handi- 
capped, through essentially zero cost alterations. 



20 



3.4 USER CHARACTERISTICS 

As noted earlier, research related to identifying travel behavior 
and needs of non-motorized groups has been limited. There is not yet 
a clear understanding of what characteristics are most influential in 
determining whether or not a non-motorized trip will be made. In 
addition, only a small number of research studies have been conducted 
to identify travel patterns, particularly characteristics influencing 
how non-motorized trips are made. Behavioral studies of crossing trips 
are virtually non-existent. Some modeling of pedestrian travel behavior 
in downtown areas has been conducted; however, this is still a very 
inexact science. 

3. A.I Pedestrian Characteristics 

Pedestrian trip generation appears to be influenced in both rural 
and urban environments by one or more of the following: 

• Perceived accessibility of major origins to destinations 

• Land use at trip origins and destinations 

• Number of total trips attracted by major generators and number 
of total trips generated by major sources. 

• Car avai labi 1 ity 

Perceived accessibility has been considered to be related to one 
or more of the following: availability of time, distance between 
origins and destinations, trip purpose, the walking environment, and 
the traveler's ability to walk. 

Again, few comprehensive empirical studies have been conducted 
to provide information about pedestrian walking patterns. In one 
study (8), an observational experiment was conducted to describe ped- 
estrians' walking patterns. It was concluded that walking space or 
distance is perceived through the perception of time. Pedestrians 
tend to: follow the simplest path; are not deterrred by the number 
of motor vehicles; walk as directly as possible to the destination 
following a straight path; and anticipate a change in direction of 
travel a long time before it occurs. In addition, several sources 
stated that walking speed varies by age and sex of the pedestrian 
and walkway grades (9, 10, 11). 

No general agreement was found as to usual walking distances. 
Estimates for the average distances of most trips ranged from 200- 
300 feet (61-91M) to over 1,000 feet (305M). 

Major conclusions about behavior when crossing intersections 
were: 



21 



• many pedestrians do not look at oncoming traffic before 
crossing; 

• people usually cross streets faster than they walk on side- 
walks; and 

• adults are more often deviant crossers than children. 

Three comprehensive investigations (12, 13, 1*0 of pedestrians' 
use of grade separations were reviewed. All of these research efforts 
were conducted in urban areas in England. The major conclusions re- 
sulting from these studies were in general agreement. It was found 
that the following factors influence the use of crossing facilities: 

• Travel time differences between crossing at-grade and using 
grade separated facilities. 

• Facility ramp length: pedestrians perceive that long ramps 
impede travel . 

• Visible locational convenience of the facility. 

• Presence of signing to direct the user to the facility. 

• Entrance design of subways. 

Some of the most comprehensive studies of pedestrian behavior in 
downtown areas have been conducted by John Fruin, Boris Pushkarev and 
Jeffrey Zupan, and Scott and Kagan (15,16,17). Major factors affect- 
ing tripmaking were concluded to be the density, size, type and quality 
(attractiveness) of major origins and attractors within a given area, 
time of day, and quality of the walking environment. Other research 
which describe characteristics influencing trip generation have been 
conducted in Toronto and Sweden (18, 19). However, identification of 
causal relationships is not very far advanced. 

Two major empirical studies (20, 21) presented the following 
conclusions about walking patterns: 

• Walking distances are generally consistent among cities of 
simi lar size. 

• Walking characteristics vary slightly by trip purpose (e.g., 
walking distances in Boston were found to be shorter for 
shopping trips than for work or social trips). 



22 



The Pushkarev, Zupan study (16) is the only research reviewed 
for which inferences can be made about use of crossing facilities 
in downtown areas. In the authors' view, pedestrians will use grade 
separations only if they are extensions of a major continuous level 
walkway on which pedestrians already find themselves. The authors 
also concluded that obvious horizontal or vertical detours will in- 
hibit pedestrians from using crossing facilities. 

3.^.2 Cyclist Characteristics 

Still less information was found describing cyclist travel be- 
havior and needs. The available material indicates that the follow- 
ing factors may influence whether or not bike trips are made: 

• Trip distance: Smith (22) concludes that cut-off points of 
maximum trip distances vary from 3 to 6 miles (4. 8-9. 7 km), 
depending upon trip purpose. 

• Route characteristics (traffic, terrain, perceived safety, 
etc.) 

• Trip purpose 

• Climate: extreme temperatures and rain are significant 
deterrents. 

• Age 

• Bike ownership 

• Car avai labi 1 i ty 

Several major conclusions related to travel behavior were found 
in the literature. The conclusions most relevant to the planning 
and design of grade separation treatments are described below (22): 

• Bike facilities are perceived by most recreational and in- 
frequent bicyclists as safer than no facilities. 

• Generally the greater the separation from motor vehicles, the 
greater is the level of safety perceived by the users. 

• Sidewalk bikeways are perceived by most users as less safe 
than on-street facilities. 

• A distance as little as two blocks out of the direct travel 
way may be considered as a significant inconvenience. 

• The average cycling speed is 12 mph (19 kmh) . 



23 



• Where there are moderate headwinds, bikes will sway sig- 
nificantly. 

• Young bicyclists are most prone to accidents. 

• The majority of bike accidents occur at intersections. 

3.4.3 Characteristics of the Handicapped Traveler 

References describing travel characteristics and needs of the 
handicapped are also rare. Most of the recent transportation studies 
are related to the need for motorized systems rather than pedestrian 
facilities. Literature identifying trip generation characteristics 
and general walking behavior tends to be based on empirical research, 
while most of the reviewed information on specific needs of the handi- 
capped is based on expression of opinions and hypothetical situations. 

The Disabled Population ; According to the 1972 National Health 
Survey, as cited by Crain and Associates (28), about 6,458,000 or 3-2 
percent of the population have a chronic mobility limitation. Of this 
population, about 1,227,000 are severely impaired visually (i.e., have 
no useful vision in either eye), while 423,000 use wheelchairs. 
According to Abt Associates (24), an additional 567,000 have acute 
conditions such as fractures and sprains, which temporarily affect 
mobility, and about 1,671,000 of the institutional population have 
other mobility limitations. 

Importance of Walking : Recent studies (23, 25, 26, 27) and in- 
terviews with disabled persons indicate that they are more reliant on 
the walk mode than are members of the non-disabled adult population. 
It can be concluded from these results that the majority of disabled 
persons depend on others for transportation unless the walk mode is 
used. It is expected that the importance of pedestrian travel will 
continue to remain high among handicapped persons. New laws (e.g., 
the recently enacted HEW 504 legislation) will mean that handicapped 
people will be able to travel further and more often as their en- 
vironment becomes more accessible. 

Current Travel Behavior : The character of pedestrian travel 
among the handicapped appears to vary with environmental setting, 
disability type and social role (e.g., employed, retired, student). 
The walking range of this study's disabled panel varied from a few 
blocks for a person using a walker to all over a small -si zed city 
for a person in an electric wheelchair. With the increase in speed 
and range of wheelchairs, severely disabled persons will be able to 
achieve trips of several miles where the path is accessible. Robert's 
study (28) of persons who are visually and hearing impaired showed 
that they averaged 10 to 14 block walking trips. The study also 
concluded that surface textures, sidewalk construction, pathway 



24 



directness and noise diffusion are influential factors in walking 
safety for the blind. Signing is particularly important to the deaf. 

Data based on empirical research indicates that the most fre- 
quent goals of walking trips among the handicapped are shopping and 
social activities. One survey in a suburban area found that health 
care was a frequent trip purpose. Another indicates that walking 
is an important source of exercise and daily recreational activity. 
Knowledge regarding the residential location patterns of the handi- 
capped can provide insight into the trip making characteristics of 
this group. 

There is some evidence in the literature to indicate (a) that the 
transportation handicapped form a higher percentage of the urban popu- 
lation than of the suburban population; and (b) that many of the handi- 
capped may locate their residences close to or within preferred social, 
religious and shopping activity centers. This seems to be particularly 
true among the elderly handicapped. 

Mobi 1 i ty Needs : Evaluations of mobility needs by Roberts (28), 
Jones (29), and Crain (23) indicate that mobility needs vary according 
to both different disability types and the severity of disabilities. 
A summary of these mobility needs by disability type is presented in 
Table 1. Jones (29), Templer (30) and others (31, 32), have also 
suggested minimum and maximum space requirements for wheelchair per- 
sons, semi -ambulatory and the blind. Most of these suggested standards 
are not based on behavioral studies, but are based on commonly accepted 
guidelines. 



3.5 CROSSING CONDITIONS 

For purposes of this study, grade separations have been grouped 
into two categories — overcrossings and undercrossings. Overcrossings 
are structures which provide passage over barriers for non-motorized 
travelers. Undercrossings are facilities which provide passage under 
barriers. All grade crossings have been defined as having three com- 
ponents, as shown in Figure 2. 

Ends : That portion of the traveled way which is adjacent to the 
physical limits (on both ends) of an over- or undercrossing and which 
affects the ability of non-motorized travelers to use the crossing. 

Approaches : The transition sections between the end conditions 
and the structure crossing the barrier. 

Structure : That protion of the traveled way actually crossing 
over or under the barrier. 



25 



Table 1. Mobility Needs by Disability Type 



Disabi 1 i ty Type 


Mobi 1 i ty Needs 


Semi -Ambulatory 


• 


Low level of toleration for 
abrupt changes in level or 
uneven walking surfaces. 




• 


May need support to rise when 
seated. 




• 


May require support where level 
change occurs. 




• 


(With Aids only) additional space 
to maneuver aids may be required. 


Wheel chai rbound 


• 


Need for even surfaces to prevent 
erratic movement or sudden stops. 




• 


Need for space to allow passage and 
maneuvering of wheelchair. 




• 


May have difficulty twisting and 
turning. 




• 


Gradual changes in level are 
necessary. 




• 


Need for guards to prevent wheel- 
chairs from rolling off sloped 
surfaces. 


Lack of Maturity or Mental Development 


• 


Simple environment with clear- 
warning signs. 


Impairment of Postural Mobility or Upper 


• 


Need to minimize required twisting 


Torso 




and turning. 




• 


Need for supports with level changes 
which are easily reached and grasped. 


Physically Restricted - Agility, Stamina, 


• 


Minimize need for sudden decisions. 


Reaction Time (Heart Disease, hypertension, 






degenerative diseases, aging) 


• 


Minimize need for quick or sustained 
movement. 


Auditory Impairment 


• 


Clear visual cues and signing to 
direct and caution. 


Visual Impairment 


• 


Unevenly distributed or unbalanced 
light sources can distort visual 
picture. 




• 


Limited if any ability to judge 
distances. 




• 


Limited if any ability to differentiate 
between color intensities. 




• 


Limited if any ability to see objects 
clearly or to focus on objects of 
different distances. 




• 


Need for tactile cues to hazards. 




• 


Difficult to compensate for 

sudden change in level or direction. 




• 


Sound diffusion likely to confuse 
bl ind persons. 




• 


Need for guards to prevent falling. 



26 



Elevation view 





Figure 2. GRADE CROSSING ELEMENTS 



Review of current practice indicated that certain factors in- 
fluence the type of planning for and implementation of crossing 
facilities. These factors or considerations have been grouped into 
(a) locational characteristics, (b) structural characteristics, (c) 
approach characteristics, and (d) end conditions. These considera- 
tions are listed below: 

3«5»1 Location Characteristics 

• School Crossings: The development of treatments to provide 
safe access to schools has traditionally received high priority 
in both the development of refined designs and in funding. 

• Central Business Districts: In areas where there is urban 
renewal, grade separated systems for pedestrians are often 
part of downtown renewal plans. 



27 



• High Activity Residential Urban Areas Outside Central Business 
Districts: Some sources indicate that these areas have the 
greatest need for grade separated facilities for non-motorized 
travel . 

• New Towns: Some of the most extensive grade separated systems 
have been built in these areas at the time the new towns were 
c rea ted . 

• Suburban and Rural Areas: Single facilities have been built 
where a clear need has been established, such as construction 
of a freeway which cuts off travel between major activity 
centers. 

• Long Bridges Over Waterways: Many of these bridges were con- 
structed without pedestrian or bike facilities. Bus transit 
has been one technique used to accommodate bicyclists and 
pedestrians. 

3.5»2 Structure 

• Over- or Undercrossings: The benefits and costs of these 
alternative treatments are sensitive to a variety of influences 
such as site condition, construction method and social setting. 

• Types of Overcrossings: According to one source (33), the 
cost and construction feasibility of downtown overcrossings 
varies by the degree to which they are integrated into build- 
ings. 

• Construction Materials: Construction and maintenance costs, 
and life span vary according to whether constructed with con- 
crete, steel, wood, aluminum, or plastic fiberglass. 

From on-site examination of crossing facilities, a typology of 
non-motorized treatments on structures was developed. The typology 
is presented below: 

• Absence of treatments on the structure for non-motorized 
travel . 

• One-sided treatments on the structure (e.g., shoulder and/or 
a walkway on one side of structure). 



• 



Two-sided treatments (an exclusive structure serving non- 
motorized travel is a special case of a two-sided facility). 



28 



3.5.3 Approach 



Ramps or Stairs: These are primary characteristics together 
with grade which determines how accessible structures are to 
bikes and the disabled. 



3.5.^ End Conditions 



Intersection or Midblock: Midblock end conditions have been 
rated as preferred from the viewpoint of safety, but they 
often result in out-of-the-way travel. 

Type of Freeway Interchange: Different configurations of 
interchanges result in varying types of solution for connec- 
tivity to structures. 

Presence of Non-Motorized Travel Facilities: According to 
sources reviewed (e.g., 33, 3*0 , treatments on ends are often 
not designed to be integrated with existing approach facili- 
ties. In cases where there are barriers to travel at ends, 
pedestrians and cyclists are prevented from taking advantage 
of structural treatments. 



3.6 HAZARDS AND IMPEDIMENTS 

Information collected about crossing hazards and impediments 
mainly consisted of opinions based on casual observation or intuitive 
judgment from planning experiences. Hazards are defined as the 
presence or absence of facility treatments which affect crossing 
safety. Impediments are defined as the presence or absence of facility 
treatments which affect crossing convenience. Few rigorous research 
efforts have been conducted to identify and compare the perceived 
hazards and impediments to non-motorized travel. There have been some 
studies (35, 36, 37), particularly related to pedestrian facilities, 
where variables related to hazards and impedences have been identified 
and quantified. However, results have not been consistent. 

3.6.1 Pedestrian Facilities 

Most of the reviewed studies point out that the main reason for 
non-use or avoidance of pedestrian facilities is inconvenience. 
According to one source (38), most people do not perceive that grade 
separations significantly reduce accident risk. Another author (39) 
stated that some people look at structures as further evidence of 
the domination of autos. Several authors (38, k0, 41, k2) claim 
that where people have alternate routes available, a grade separa- 
tion needs to reduce the time of crossing to be competitive. 



29 



The following types of crossing hazards were identified in one 
or more of the reviewed studies: 

• No sidewalks on crossings where there is motor vehicular 
traffic 

• Grades too steep for safe travel 

• Inadequate separation from motor vehicle traffic 

• Facility approaches which require crossing of high speed 
freeway interchange ramps 

• On some facilities where there is a high level of structural 
sway due to low live load standards, users tend to perceive 
that the structures are unsafe. 

In addition, reviewed sources (36, A3) identified a hazard 
associated with overcrossings over roadways which affect motorists. 
Low railings on overcrossings allow facility users to throw objects 
onto the roadway below. 

It was pointed out that often safety is the reason cited for con- 
struction of grade separations. From study of national accident 
statistics, some authors (35, M, 45) concluded that high risk areas 
for pedestrian accidents are crowded, older residential areas outside 
central business districts and freeways where pedestrians are not pre- 
vented from crossing traffic streams. 

The reviewed literature identified several impediments associated 
with pedestrian use of grade separations: 

• Level Change: amount of climbing and descending required. 

• Lack of Continuity: awkward transition to continuing facil- 
ities on either side of structures; signs, and street furni- 
ture obstructing pathways. 

• Lack of Directness: sight distance restrictions; facilities 
not in direct line with major attractors and generators or 
crosswalks on either side of the facility. 

• Insufficient Capacity: pedestrian congestion, particularly 
in downtown areas. 

• Lack of Protection from the surrounding atmospheric environ- 
ment: exposure to motor vehicle pollution, traffic noise, 
and adverse weather conditions, such as rain, wind and snow. 

• Lack of Coherence and Interest: winding or monotonous path- 
ways. 

30 



Impediments associated with subways -- i.e., underpasses for 
pedestrians — are poor lighting and security resulting from poor 
sight distance. One author (46) stated that subways represent "life- 
lessness." Another (39) perceived subway impediment as unsanitary 
or unaesthetic environmental conditions and encouragement of vandalism 
attributable at least in part to limited sight distance. If well- 
designed, however, there is evidence that pedestrians prefer subways 
to overcrossings (12). 

3.6.2 Bicycle Facilities 

Reviewed sources (47, 48, 49) indicate that bicyclists and ped- 
estrians generally experience the same crossing hazards and impedi- 
ments. However, authors generally agree that underpasses rather than 
overpasses are preferred among cyclists, due to the less steep slopes 
and because momentum gained going down helps bicyclists overcome the 
up slope. Hazards of particular importance for bicyclists which 
were mentioned are: 

• Traffic lanes too narrow for sharing by motor vehicles and 
bikes. 

• Steep grades which significantly reduce cyclist control. 

• Storm sewer grates with bars parallel to the curb. 

• Too low rail ings. 

• Snow, ice, or debris obstructing the pathway. 

• Overhead or lateral obstructions. 

• Signs and street furniture obstructing the pathway. 

• Shared bike and pedestrian facilities where there is a large 
differential in travel speeds. 

• Intersection Conditions: A frequently cited example is where 
bike facilities on a crossing structure are provided on one 
side only, while cyclists on the approach are expected to ride 
directional ly (i.e., on the right). Such designs place 
cyclists in the predicament of either riding in a traffic lane 
or having to make two crossings of the street at each end of 
the facility. 

Impediments of particular importance to cyclists, other than those 
mentioned for pedestrians, included: 



31 



• Stairs - a barrier to riding. 

• Squared Curbs - an obstruction to travel if a sidewalk- 
to-street transition has to be made. 

3.6.3 Handicapped Facilities 

Documents summarizing design criteria for handicapped facilities 
were found to be the primary source for identifying hazards and impedi 
ments (23, 61, 63). Relatively few documents were found which dis- 
cussed the problems of the handicapped pedestrian. One of the main 
findings of the literature review was that hazards and impediments 
vary for persons with different types of handicaps. Hazards and im- 
pediments of particular importance to the handicapped are listed 
be 1 ow : 

Hazards 



• Excessively steep grades on approach ramps. 

• Slick surfaces due to poor drainage or use of improper 
construction materials. 

• Abrupt (squared) nosing on stair treads. 

• Obstructions on the sidewalk or walk area. 

• Overhanging obstructions. 

• Drain inlets and storm drainage channels located in inter- 
sections. 

• No handrails or handrails which do not allow a firm grasp. 

• Loose debris on sloping surfaces. 

Impediments 

Sources reviewed (2k, 30, 31) indicate that major impediments to 
the disabled are long distances (over 100 feet or 30.5 meters) where 
there are no areas to rest which do not obstruct other travelers. In 
addition, the lack of curb cuts in approach areas and stairs are 
repeatedly mentioned as barriers to the wheelchai rbound. However, one 
author (50) points out that ramps are an impediment to travel by per- 
sons with leg braces or crutches; ramps are more difficult for this 
group to negotiate than stairs. 



32 



3.7 DESIGN STANDARDS AND APPROACHES 

3.7.1 Design Standards 

The most common reference for design standards for bicycle and 
pedestrian facilities are the American Association of State Highway and 
Transportation Officials (AASHTO) publications — Guide for Bicycle 
Routes , 197^, and A Policy of Urban Highways and Arterial Streets , 1973 
(51, 52). (FHWA is in the process of developing their own design 
standards for bicycle facilities.) The recommended widths of bike 
trails and sidewalks, overhead clearances, grades, barrier rail types, 
and the characteristics of bicyclists and pedestrians, may be found in 
these publications. The heavy reliance on these sources by many 
agencies means that design standards often used are only as current as 
the most recent editions of these references. Some cities and states 
have developed their own manuals (^3, 53» 5*t, 55); often incorporating 
AASHTO standards as well as local criteria. 

Standards for handicapped design are currently undergoing major 
upgrading and revisions. At present, there is some confusion and 
trepidation among designers about accommodating the handicapped. 
There is no widely used standard reference, equivalent to the AASHTO 
publications, for handicapped facilities on grade separations. 

3.7.2 Accommodating the Non-Motorized 

Facilities for bicyclists, pedestrians and the handicapped on 
over- and undercrossings are provided in two ways; either as part of 
newly constructed projects, or modification (retrofitting) of existing 
over- or undercrossings. Both types are briefly reviewed in this 
section. 

Facilities for the Non-Motorized in New Projects : Bicycles and 
pedestrians often travel on sections of over- and undercrossings whose 
main purpose is the movement of automobiles. Where facilities for non- 
motorized travel are shared by bicycles and pedestrians, an eight foot 
(2.4 M) wide sidewalk physically separated from automobile traffic is 
sometimes provided, usually on one side of the structure. Another 
common treatment is to provide a shoulder or wide curb lane to accom- 
modate bicycle travel. The extent of separation between motor vehicles, 
bicyclists and pedestrians is dependent on the speed and volume of 
automobile traffic, and ranges from widened curb lane to a full barrier 
separation. 

In many instances, sidewalks for pedestrians with a four to six 
foot width (1.2-1.8 M) are installed on one or both sides of an over- 
pass or underpass. Bicyclists have the option to ride or walk their 
bikes on the sidewalk or continue across the structure in the roadway 
or on the shoulder or clearance area between the edge of the traveled 
way and the curb or barrier. 

33 



A fairly common method of retrofitting a bridge structure for 
pedestrian use is to cantilever a walkway from the outer edge. This 
construction is easiest if the bridge is composed of steel beams, since 
the walkway can be fastened to the edge with a combination of welded 
and bolted connections. Fastening cantilevers to reinforced concrete 
structures is also fairly simple. Railings are provided on the out- 
side of the walkway. 

Due to structural limitations, both types of retrofits cited 
above tend to have narrow, three to four foot wide, (0.9-1.2 M) walk- 
way areas, Bicyclists have the option of walking their bikes on the 
pedestrian walkway or riding on the roadway. 

Additional discussion concerning current practice can be found in 
Chapter 6 of this report, which describes the results of the field 
evaluations carried out at a number of existing over- and undercross- 
ings. 

Where conditions warrant, separate overpass and underpass struc- 
tures are constructed exclusively for bicyclists and pedestrians. 
These structures are usually built as part of recreational bike or 
pedestrian trail systems (for example, through parks); for access to 
special facilities expected to have a high volume of non-motorized 
travel, such as stadiums; or where residential areas are separated from 
community facilities (shopping centers, schools, recreation areas) by 
highways or other barriers. Grade separations are also becoming more 
commonplace in central business districts as part of new construction 
or redevelopment where aerial walkways connect buildings and elevated 
plazas. 

These overcrossings generally have a clear width of 8 to 12 feet 
(1.8-3.7 M) between railings or curbs. The width of the structure and 
the actual design loads are determined more by the need for mainten- 
ance vehicle access than for bicycle and pedestrian use. Depending 
on desired structure length, site conditions, and most economical 
material use, the construction can consist of prestressed concrete 
girders, single span welded plate girders with reinforced concrete 
deck, wood beams with wood decking, or steel through trusses. 

Underpasses built solely for pedestrian and bicycle travel exist 
in much fewer numbers than do overcrossings. This is largely due to 
maintenance and social problems, and vandalism. Where these features 
are most critical, underpass utilization is low or the structure has 
been removed from service. Minimum heights for pedestrian and bicycle 
underpasses are usually eight to nine feet (2.4-3.1 M) , while minimum 
widths vary from 8 to Ik feet (2 . 4-4. 3 M) • Some jurisdictions have 
attempted to adjust the proportions of pedestrian underpasses in an 
attempt to overcome the psychological barrier associated with a long, 
narrow tunnel. The City of Chicago has a standard tunnel width ratio 
of one-quarter of the length, with a maximum width of 2k feet (7.3 M) . 
Pedestrian underpasses are commonly arch shaped and constructed of 
reinforced concrete or steel plate. 

34 



CHAPTER 4 

NEEDS ASSESSMENT 

4.1 INTRODUCTION 

A variety of methods to deciding whether or not to incorporate 
non-motorized facilities into over- and undercrossings are possible. 
These can vary from basic application of judgment or direct compliance 
to an adopted policy to consideration of a full range of implications 
and impacts, together with multiple iterations of public participation 
and reviews. Even though there may be many similarities between 
sites, individualized characteristics oftentimes produce marked differ- 
ences, thereby influencing both need assessment and design requirements 

This chapter provides background on the current warranting 
practice, as well as presents a recommended generalized approach or 
needs assessment procedure within which most situations can be evalu- 
ated. 



4.2 WARRANTS 

A basic cornerstone of good design and traffic engineering prac- 
tice is that similar circumstances or situations should be given 
similar treatments, and where certain combinations or conditions are 
present, a "need" or warrant exists for a specific type of control or 
facility. Warrants can be defined as criteria or measures of need 
which serve as guidelines in the process of deciding whether a par- 
ticular form of physical improvement or traffic control should be 
implemented. Since warrants describe general conditions, they should 
be viewed as guidelines only, and not as hard and fast rules for the 
installation or rejection of facilities or devices at a specific site 
without considering its individual conditions and circumstances. 

4.2.1 Purposes of a Warrant 

Warrants have been established for the following purposes: 

• To utilize criteria reflecting actual experience 

• To provide a rational basis for decision-making 

• To promote a more effective application of funds 

• To avoid the installation of facilities or devices where they 
are not needed or could be detrimental. 

The application of warrants is most effective when coupled with 
qualified engineering judgment and consideration of all pertinent 
facts, whether quantifiable or not. As applied in current practice, 
ascertaining the degree to which various warrants are satisfied is 
but one step in the decision-making process, which justifies and 

35 



ultimately authorizes construction of facilities or implementation of 
devices. 

4.2.2 The Need for Warrants 

It might well be asked, however, whether correct and defensible 
decisions regarding non-motorized facilities can be made without follow- 
ing a warrant process. The answer is both yes and no. 

• The answer may be YES if the evaluation is conducted by a team 
of skilled designers, planners and advisory groups thoroughly 
knowledgeable about both grade separations and local condi- 
tions. Such an evaluation process would typically contain many 
of the elements considered as warrant criteria. The degree of 
success of this process is directly proportional to the skill 
and level of knowledge possessed by the participants. 

• The answer is probably NO if less experienced or less know- 
ledgeable persons analyze the criteria and/or where political 
prerogative is excessively applied to satisfy vocal but inade- 
quately informed demands. In these situations, the chances 
for effectively analyzing the problem markedly decrease and 

it becomes more likely that facilities approved in this fash- 
ion will ultimately prove to be deficient in some way. 

Frequently when warranting procedures are not used it is because of 
lack of knowledge about available procedures, rather than a knowing 
rejection of the concept. 

There is little doubt that an organized review of available in- 
formation is a more valuable tool for decision-making than a haphazard 
approach. A logical, structured and consistent approach is also more 
likely to be understood and accepted by both technicians and lay 
people concerned with the crossing. However, warranting procedures 
with complex or excessive input needs may discourage warrant use and/ 
or acceptance of results. In essence, this may force users to avoid 
the process entirely. 

4.2.3 Warrant Types 

• Economic Warrants - are based upon a comparison of construction 

and maintenance cost to monetary benefits 
anticipated from providing the facility or 
dev i ce . 

• System Warrants - consider to what degree the proposed facility 

is an essential component of an entire 
system. 



36 



• Threshold Warrants - state that a certain combination of factors 

must exist to justify implementation. 

• Point Warrants - employ selection or assignment of numerical 

values to quantify various factors. Facili- 
ties can then be compared to a base level 
figure and be ranked relative to other can- 
didate sites. 

To these four systematic warrant procedures should be added two 
other related and important criteria of the decision-making process, 
namely: established policy and political prerogative. 

• Established policy - can define predetermined guidelines 

affecting various aspects of non-motorized 
travel, thereby eliminating or reducing 
the need for action justified by the war- 
rant process. A decision to make al 1 
facilities accessible to handicapped 
travelers as a matter of public policy, 
for instance, is one example of such a 
guidel ine. 

• Political Prerogative - can complement or bypass the warranting 

evaluation process. Design responsiveness 
to publ ic preference (expressed through a 
community involvement process or through 
elected political representatives) is a 
valid consideration which should be ex- 
plicitly recognized. However, problems 
can occur when decisions are largely based 
on emotion and political pressure, rather 
than on rational review of advantages and 
disadvantages. 

k.l.k Use of Warrants 

It appears on the basis of available information that justifica- 
tion of non-motorized facilities on new grade separations shared with 
motorized vehicles is seldom rigorously analyzed, unless the structures 
are long or unusual in some way. Many design decisions for ordinary 
highway bridges are resolved by applying a given policy. This may 
mandate inclusion of non-motorized facilities where such facilities 
exist on the approach, or it may specify that space, such as a shoulder, 
be included to serve as shy distance or as a safety zone for stopped 
vehicles. Such space can also be used by non-motorized travellers. 



37 



Recommendations for retrofitting structures for non-motorized 
facilities are typically based on responses to experience with exist- 
ing use and observed deficiencies or are designed to provide contin- 
uity along a travel corridor. 

In summary, the most rigorous justification techniques for non- 
motorized facilities appear to be directed toward new, exclusive 
pedestrian (bicycle) grade separations or for long structures shared 
with motor vehicles, where the total cost of such non-motorized 
facilities may amount to large sums of money. Established policies 
and political prerogative are other important factors in determining 
whether, and to what degree, non-motorized facilities will be included 
in over- and undercrossing designs. 

k.2. 5 Current Warrant Systems 

Most of the warranting systems devised to date for non-motorized 
facilities have been directed toward determining the need for exclus- 
ive pedestrian facilities. Assessment of the need to develop bicycle 
facilities has been treated to a lesser degree, although the recent 
resurgence of bicycling has resulted in increased effort to establish 
better means of facility justification. Justification for making 
facilities accessible to handicapped pedestrians is another area which 
has been almost entirely neglected in the past, but which is now re- 
ceiving considerable attention. 

Economic Warrants . These can be useful, especially where facil- 
ity costs can be compared directly to the cost of alternative strate- 
gies such as installing a traffic signal, busing, or providing an adult 
crossing guard. Scott and Kagan (17) list various aspects of costs 
and benefits of facilities for pedestrian crossings of highways. 

Cost factors can be grouped as follows: 

- base facility construction costs 

site specific facility construction costs 

annual cost of facility operation and maintenance 

facility economic investment cost 

They found the most often overlooked items with regard to costs 
to be: 

- Annual maintenance cost 

- Vehicle delay during facility construction 
Right-of-way costs at the end conditions 

- Effects of span lengths and total facility length 



38 



Benefit factors of grade separated pedestrian crossings included 
improved linkage between land uses, as well as reduced costs related 
to: 

- Vehicle Delay Time 
Vehicle Operation 

- Pedestrian Injury and Fatality 

- Alternative Crossing Controls 
Pedestrian Roadside Delay 
Pedestrian Trip Delay 

According to Scott and Kagan (17), potential utilization of the 
facility must be determined and if less than 100 percent then the 
gross benefits are reduced accordingly to net benefits. 

System Warrants . Use of this process is facilitated by adop- 
tion of a master plan specifying pedestrian and pedestrian and 
bikeway elements. Master planning typically explores a variety of 
alternatives and identifies linkages important to the creation of 
a comprehensive and coordinated network of pedestrian and bicycle 
facilities. The ultimate plan involves technical as well as public 
participation to assure satisfaction of community needs. Subsequent 
proposals for non-motorized facilities are then simply checked for 
consistency with the adopted plan (56). 

Threshold Warrants . These state that if a certain combination 
of factors exist, then a structure is justified. Certain fundamental 
criteria must also be met before a grade separation structure is 
considered to be justified. Basic to all situations are: 

- Existence of permanent conditions requiring the crossing 
(i.e., not just a temporary condition or need). 

- Engineering feasibility of the proposed facility. 

In addition, other factors come into play depending upon the 
degree of access control on the highway to be crossed by an exclusive 
pedestrian/bicycle facility. For instance, the State of Washington 
(57) specifies that one of the following items must be satisfied when 
crossing fully controlled access highways: 

- At least 200 pedestrians crossing per hour for two hours each 
day; if there were no structure, the additional average walk- 
ing distance required for 85 percent of the pedestrians having 
the shortest walking distance exceeds one-half mile. 

- The severance damages for the taking of property shall be more 
than the cost of the structure or structures necessary to cure 
the severance. 



39 



Structures proposed to cross partially controlled and non-control- 
led access highways must satisfy any one of the following, plus the 
fundamental criteria listed above: 

- An economic analysis indicates that the yearly cost of the 
separation structure is less than the yearly cost of install- 
ing and maintaining the required signal (s) and appurtenances 
(signs, crosswalk painting, fencing, etc.). Before making 
this comparison, additional average walk distance required for 
85 percent of the pedestrians having the shortest walking dis- 
tance must exceed one-half mile, if there were no structures. 

- The vehicular and pedestrian traffic is so great that a 
traffic signal could not handle both without being overloaded 
during peak hour traffic. 

Point Warrants . This method is based upon the realization that 
there are a number of factors which influence the need for a grade 
separation. Efforts are then directed toward identifying these factors 
and assigning appropriate point values. Summation of all values pro- 
duces a score which can then be utilized as a comparison or ranking 
tool. By applying the same methodology to other sites being evaluated, 
it is possible to draw conclusions about the relative need of each. 

The City of Seattle, Washington (58) and the Institute of Traf- 
fic Engineers (56) (now Institute of Transportation Engineers), were 
early advocates of the point method of warranting pedestrian separa- 
tion facilities. While both recognized the difficulties in assigning 
weights or values to intangible items, they found the method generally 
satisfactory in providing a working tool for those persons responsible 
for placement of pedestrian separations. However, both groups caution 
users that the system was not an automatic and infallible selector of' 
locations. They stressed that it was intended to provide the skele- 
ton upon which enlightened judgment of engineers and planners could 
be placed and that the system was empirical in nature, which makes 
any and all parts subject to challenge. 

The Seattle point ranging system (58) was calibrated by rating 
27 existing and 36 proposed overpasses and was found to provide a 
reasonable measure of reliability. The factors utilized for the 
priority ranking system were measurable characteristics, considered 
common to all crossing situations. The weighted values for these 
factors, as refined from the Seattle experience, are as follows: 



ko 



Factor 

Vehicle and pedestrian volume 
Accident experience 
Miscellaneous and vision factors 



Value 

kO percent maximum 
15 percent maximum 
45 percent maximum 

100 



A nomograph was developed to derive vehicle and pedestrian 
volume percentages. In Seattle it was found that there was a maximum 
number of correctable pedestrian accidents occurring at any inter- 
section during the previous five-year period. Therefore, the ranking 
system assigned five points for each correctable pedestrian accident, 
without regard to severity. 

Miscellaneous factors were weighted, as follows: 



Factor 

Marked School Crossing 
Elementary School Crossing 
Presence of Adult Crossing Guard 
Vision, Growth, Street Width, 
Speed, Capacities 



Points 



10 


10 


10 


15 



k5 



A salient thought expressed in the Seattle study (58) was that 
the priority system will at best be a guide to administrative decision 
since it is based upon many estimates and judgments. The writers 
cautioned that the system should not become so burdensome as to demand 
more time and measurement than the level of accuracy it can produce 
on the end product. 

In a recent study, researchers from the New Jersey Department of 
Transportation (59) expanded upon the concepts developed in Seattle 
and adopted by the Institute of Transportation Engineers (ITE) for 
exclusive pedestrian grade separations. Refinements included separat- 
ing the evaluation into two categories and selecting appropriate 
factors for each. These are as follows: 

• Where pedestrian activity exists: 

1. Pedestrian and vehicle volume with peak hour delay factor. 
(kO points max) 

2. Actual versus desirable sight distance at unsignalized 
locations, or pedestrian crossing time versus maximum green/ 
yellow time at signalized locations. (50 points max) 



k] 



3. Number of school children and type of crossing protection. 
(30 points max) 

4. Distance to nearest alternative crossing, considering pro- 
tection there. (30 points max) 

5. A judgment value. 

• Where pedestrian activity is not currently possible: 

1. Pedestrian trip generation. (70 points max) 

2. Distance to nearest alternative crossing, considering pro- 
tection there — flashing signal/signs only/no signs (70 points 
max); traffic signal (60 points max) and Grade Separation (50 
points max) 

3. A judgment value. (60 points max) This includes Safety of 
Alternate Crossing (5 points max); Surplus Trip Generation 
(1 point for each 15 trips in excess of 700 per day) and 
Origin of Location (35 points max) 

Calibration of pedestrian trip generators was segregated into five 
categories: 

1 . Bus Stops 

2. Commercial 

3. Schools 

k. Institutional 
5. Recreational 

It was decided to select the single most dominant trip generation 
category where more than one land use was present. If the same land 
use type existed in each zone, then the corresponding trip generations 
would cancel one another (i.e., travel was assumed to be local and not 
cross the barriers). 

Ten charts and graphs were prepared from which various point 
scores could be determined. A series of three computer programs were 
developed to facilitate data processing and to compute the following 
information: 

1. Peak hour pedestrian delay at intersections. 

2. Priority ranking score for each location based on delay data 
and data collected in the field. 

3. Formated priority ranking designed to accept additional 
scores and rerank previous listings accordingly. 



kl 



Another team of researchers from Stanford Research Institute (SRI) 
independently assessed the benefits of separating pedestrians and 
vehicles (60) . The objective of this research was to identify and 
develop techniques for quantifying all of the significant direct and 
indirect benefits associated with the separation of pedestrians from 
vehicles and to develop a methodology for relating these benefits to 
the evaluation of proposals for separation. 

Four major categories (Transportation; Safety Environmental/ 
Health; Residential/Business; and Governmental and Institutions) were 
identified which are comprised of a total of 11 impacted groups. 
Each group is characterized by two to four variables identified dur- 
ing the project.* Some of the variables were further stratified 
where there were more detailed measures. A unitless scoring scale 
was developed for each of the 36 variables identified during the 
project. A +10 unit is the maximum positive value and a -10 unit is 
the maximum negative value. A zero denotes neutral or not applicable. 
The various measurement techniques can be summarized as follows: 

1. Selection of Score from Table 

Use a table to find the score corresponding to an actual measure- 
ment or observation. 

2. Simple Formula 

Insert observed and/or appropriate unitless value into preset 
formula to calculate total score. 

3. Summed Table Values 

Select applicable components from a table and then sum values to 
find the total score. 

4. Separately Scored Components 

Select the appropriate value from the scoring range for each 
component, then sum values to produce a total score. 

5. Weighted Formula 

Insert measurements or values into a formula that can be adjusted 
or weighted to produce a score which maintains its comparability 
to scores of other facilities. 

6. Qualitative Scoring 

Assign a score to a subjective variable based upon judgment 
and the guidelines given. 



* These are listed in the Appendix. 

hi 



The SRI authors (60) believe that their defined methodology is 
a flexible and responsive tool which is both comprehensive and con- 
sistent, and which makes the decision-making process easier. They 
state that the techniques can be used even if specific values for 
individual variables or components change over time. 

4.2.6 Warrant Data Availability 

Some insight into the kind and amount of data used in justifying 
over- and undercross ing facilities for non-motorized travel can be 
obtained by reviewing relevant experience elsewhere. 

On-going warrant systems in the states of Alaska, California, 
Kentucky, New Jersey, Texas and Washington were reviewed to deter- 
mine data requirements. I terns commonly considered of primary import- 
ance include accident experience and vehicular and pedestrian volumes. 
Accident data is city wide, whereas volume counts and other planning 
data are most often taken in high activity areas. Other primary 
evaluation factors are sight distance, location and type of traffic 
control devices, location of adjacent crossings, permanence of the 
factors requiring the crossing, and basic engineering feasibility. 

It should not be surprising that readily obtainable data is often 
featured in evaluating the need for a structure. Data most often used 
in the needs assessment process can be grouped into the following 
categories: 

• Traffic Characteristics 

• User Characteristics 

• Land Use and Zoning 

• Crossing Location 

• Cost 

• Miscellaneous Factors 

The list of possible evaluation factors is a long one. To "pre- 
cisely" derive values for each of these items would be a major task 
for most agencies. In addition, the accuracy and degree of precision 
that can be obtained for some items is questionable. 

Pedestrian and bicycle facility needs analysis requires accumu- 
lation and review of data resources to gain a thorough understanding. 
Some data can be found in existing files, while other data must be 
collected in the field. In addition, there are a number of subject- 
ive features which have some degree of influence in determining the 
need for pedestrian and bicycle facilities. For these, there are 
no readily acceptable numerical values. Therefore, ranking systems 
must be devised to facilitate comparative analysis. Wherever possi- 
ble, such ranking systems should involve a variety of analysts with 
different viewpoints and value systems so as to minimize the possi- 
bility of bias. 



4.3 RESEARCH EXPERIENCE 

Based upon our research experience with the 72 case studies and de- 
tailed site evaluation, we believe that there should be a great deal 
of flexibility in a needs assessment process of evaluating over- and 
undercrossings, since in most situations individualistic site charac- 
teristics are dominant or decisive considerations. Examples of this 
individuality can be found in the six site evaluations studied in this 
project. 

4.3.1 Palo Alto, California 

Palo Alto established justification for a facility on the basis of 
a combination of high bicycle usage along bordering arterials and identi- 
fication of a special site opportunity to supply a missing linkage in 
their bikeway network by connecting two cul-de-sac streets. Current 
usage exceeding 500/day is indicative of the appropriateness of this 
justification process. 

4.3.2 Sunnyvale, California 

The City of Sunnyvale and the California Department of Transporta- 
tion responded to continuing community concern about the need for school 
children to travel through one of two busy freeway interchanges to 
reach school or a regional park. While estimates of usage were avail- 
able for some time, action did not occur until it was decided by the 
State that the previously planned improvements to the interchanges 
would not occur. There then began a long period of evaluation of the 
proposed exclusive pedestrian overcrossing. This included recommenda- 
tions with regard to facility design and location by engineers, based 
on technical knowledge. These concepts were ultimately modified by 
citizen input based upon a blend of desire to have the facility but 
concern about the impact the facility would have upon the adjacent 
homes. (Current usage is estimated as being 150-250/day .) 

4.3.3 Eugene, Oregon 

In Eugene, Oregon, improvements were based on the fact that a bike- 
way system had been planned and development was geared to completing 
the important links. Construction of the SPRR underpass came about be- 
cause users were crossing the tracks at-grade to gain access to the 
existing Autzen bicycle/pedestrian bridge across the Willamette River. 
This well-used unofficial crossing of the railroad was then identified 
as a link in the bikeway system and the undercrossing was built to 
assure safety. (Estimated usage 500-1 , 500/day.) The Ferry Street 
Bridge improvements responded to existing usage and travel patterns 
documented by field studies. This facility was also a vital link in 
a bikeway master plan and reduced bicyclists and pedestrian exposure 
to heavy volumes of fast moving traffic. (Current usage is estimated 
as being 500-1 , 500/day.) 

45 



4.3.4 Hampton, New Hampshire 

The retrofit of the highway bridge carrying Route 1 over the B&M RR 
in Hampton, New Hampshire, responded to a perceived safety problem along 
a route used by bicyclist and pedestrians. The existing highway over- 
crossing facility ascended a grade in order to go over the railroad and 
the width of roadway was felt to be too narrow to facilitate heavy 
vehicular traffic and bicycles. Route 1 was also identified on the 
State Master Plan for bikeways. The facility serves local demand year 
around as well as recreational bicycling in the summer tourist season. 
(Current usage is estimated as being 50-150/day.) 

4.3.5 Maryland 

The undercrossing of Route 1 83 in Maryland resulted from coordina- 
tion between government agencies. A previously planned overcrossing of 
a creek was evaluated by staff to identify opportunities to create a 
trail undercrossing. The discussions centered upon location of such an 
undercrossing, with the final judgment being to slightly modify the 
four-cell culvert to accommodate a walkway. Provision of some sort of 
hiker-biker facility maintained accessibility along a green belt corri- 
dor which was planned to serve future recreational and local circulation 
needs. (Current usage is 0-10 per day prior to completion of trail 
system. After trail completion, estimated usage would grow to 50-200.) 

4.3.6 Austin, Texas 

Experience with bicycling and walking through a complex highway 
interchange led planners and engineers in Austin, Texas, to conceive 
an off-street pathway system. The interchange area was a focal point 
for several intersecting planned and existing trails, so implementa- 
tion was based upon system as well as perceived safety concerns. 
(Current usage is estimated as being 100-200/day.) 

4.3.7 Summary and Conclusions 

In summary, the six sites studied, all relatively successful treat- 
ments, were justified (or warranted) on radically different bases. 
Case (a) involved high usage and a special site opportunity to supply 
or improve the quality of a network linkage. Case (b) involved rela- 
tively light usage but a reasonable perception of hazard to a particu- 
larly sensitive group — school children. Case (c) involved elimina- 
tion of hazards or barriers on an extremely heavily used route. Case 
(d) involved relatively light usage, but the nature of the route and 
the site were felt to justify the action taken. Case (e) involved 
moderate usage projection and justification was driven by system 
considerations -- the desire to provide a continuity linkage on a 
regional trails system -- and the ease of incorporating the facility 
in a new construction project. Case (f) involves a moderate usage 
where the project was undertaken to improve and formalize a linkage 
already being used informally. A similar pattern of diverse justifica- 
tions was found for the sites reviewed in less detail during the study. 

46 



Based on the research conducted, it is our clear finding that 
facilities must be justified by considering a range of criteria includ- 
ing known or expected use, cost, safety considerations, system linkage 
factors and sensitivity of users or sensitivity of the public to user 
needs. Quantitative or qualitative value can be estimated or measured 
within each of these criteria sets and our report extensively cites or 
presents methodology for determining valuations on each criterion. 
However, there is no single formula or warrant which aggregates the 
individual criteria to give a "Build-No Build" decision, nor should 
one be formulated. Flexibility is needed once intelligent valuations 
have been made within each criterion to allow local decision-makers to 
weigh the relative importance of the various criteria in light of their 
own particular situation. The flow chart on Figure 3 rationalizes the 
fundamental evaluation steps to be taken in the needs assessment pro- 
cess. But it is our conclusion, based on the research conducted, that 
it would be wrong to impose a rigid formula or warrant for reaching 
final decisions regarding justification of over- and undercrossing 
facilities for use by bicyclists, pedestrians and the handicapped. 

k.k NEEDS ASSESSMENT PROCESS 

Current experience with the planning for bikeways and pedes- 
trian grade separations provides a good basis for understanding 
the factors to be considered and the data needed to assess the 
desirability of providing new or retrofit over- and undercrossings 
for use by bicyclists, pedestrians and the handicapped. The need 
for including intangible factors and items that cannot be quantified 
but only ranked qualitatively, in addition to numerical data, should 
be particularly noted. 

The needs assessment procedure must be flexible enough to allow 
proper consideration of special circumstances and differences among 
jurisdictions and among sites within the same jurisdiction. Once a 
needs assessment procedure is set up which is responsive to local 
needs, it should be applied consistently and uniformly without bias 
if its results are to be credible. 

Described below is a recommended generalized approach which is 
believed to be applicable to the majority of situations likely to 
be encountered. The process is depicted graphically in Figure 3. 
As can be seen in the figure, the process has been divided into 
seven categories of activity. These include identifying problems 
and potential sites; data gathering; examining alternatives; deter- 
mining if mandatory preconditions exist; reviewing warrants and 
criteria, establishing priorities; and implementation action. Each 
of these categories is briefly discussed in the following text, 
approximately following the logic flow and decision branches indi- 
cated in Figure 3. 



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48 



4.4.1 Identify Problems and Sites 

The initial step in the needs assessment process is to identify 
the problem. This can occur as a result of staff, citizens organ- 
izations or community leaders who become aware of a deficiency or 
an opportunity with regard to bicycle and pedestrian facilities and 
who initiate steps to begin the process of analysis. One common 
example of a problem would be where accident experience is frequent 
or particularly severe, or where potential for hazardous conflicts 
is high. Another illustration is where a highway facility is to be 
constructed or modified, thereby creating an opportunity to upgrade 
bicycle and pedestrian facilities. Preliminary identification of 
potential alternative sites to evaluate is directly related to 
problem identification. 

4.4.2 Data Gathering 

Once a site is identified as a candidate for new or improved 
bicycle and pedestrian facility on an over- or undercrossing, basic 
data needs to be assembled about its physical and potential or 
actual user characteristics. Where possible, data should be gath- 
ered or derived from existing files, although some new field work 
may be necessary. The data provides background information to be 
used when evaluating alternatives and determining need, and in- 
cludes material such as: 

Type of Barrier . Barriers to non-motorized travel generally 
fall into two categories — absolute and disincentive. 

Absolute Obstacles . Features which physically or legally pre- 
vent all crossings are considered to be absolute obstacles. 
Therefore, potential trip makers must either circumvent the 
barrier or not make that particular trip at all. Examples 
of absolute obstacles include natural features, such as 
mountains, canyons, and water, as well as man-made barriers, 
such as freeways, railroad embankments, canals and fences. 
Absolute obstacles may be extensive or relatively site specific. 

Disincentive Obstacles . These discourage or inhibit non- 
motorized t ravel by providing a quality of travel which is 
marginal or less than acceptable. Therefore, some users will 
tend to totally avoid or decrease their frequency of use along 
routes which include, for example, long or steep grades, in- 
sufficient space allocations, poor maintenance, heavy traffic 
volume, and traffic control deficiencies. Disincentive obstacles 
may be psychological, as well as physical. For instance, routes 
that are perceived as dangerous, even though the facilities are 
technically adequate. Excessive noise, heavy traffic, isola- 
tion, and the threat of crime are some of the elements which 
influence user acceptance or rejection. 



49 



Site Characteristics . Descriptions of physical attributes of 
the site which may influence the operation or desirability of the 
site should be assembled. Data would include such features as top- 
ography, existing land uses, traffic control devices, dimensions, 
alignment and quality of adjacent highway, bikeway and pedestrian 
facilities, traffic volumes and accident experience. 

Existing and Planned Alternative Routes and Modes . The presence 
and characteristics of existing alternative routes/transportation 
modes should be determined. Distances from the candidate site and 
the degree of accessibility to bicycle and pedestrian travel should 
be identified. Existing transit routes and schedules and any future 
plans to expand or to implement transit service should be noted. 
Future plans to construct or modify routes or structures which could 
be an alternative route should also be identified, along with the 
approximate timetable for implementation. 

Existing and Future Impediments or Hazards to Non-Motorized 
Travel . Impediments and hazards to non-motorized travel within the 
tributary area for the candidate site should be identified and eval- 
uated to determine their distribution and order of magnitude. (See 
Section 3.6 and Tables 13 and 1*t.) Potential projects affecting 
the ability of non-motorized users to gain access to the site should 
also be identified. Similarly, projects which may be abandoned, 
thereby adversely affecting non-motorized accessibility, should also 
be noted. 

User Types and Demand . Information on pedestrian and bicycle 
mix and age distributions, together with a knowledge of primary trip 
purposes, is important to the needs assessment and design process 
for over- and undercrossing sites. In some cases, existing travel 
patterns and behavioral characteristics will indicate existing and 
even future use potential. Other situations will require estimates 
to be made to determine patronage because sites have either restrict- 
ed or nonexistent usage before the improvement is made. The tech- 
nique reported by Templer (61) for measuring pedestrian activity 
provides useful guidance for estimating over- and undercrossing 
patronage. The technique recognizes differences in data availabil- 
ity and staff availability and expertise required to produce the 
estimates. Essentially, the process is comprised of three methods. 
Utilization of data available from already completed origin destina- 
tion studies is one method. A second approach involves gathering 
data about residential population distribution; concentrations of 
trip destinations, primarily in non-residential areas (shopping, 
office, service-institutional recreational, etc.); locations of 
special attractors of bicycle, pedestrian and handicapped travel; 
and trip making patterns and preferences. The third method is in- 
tuitive, relying upon detailed and accurate personal knowledge of 
members of an advisory panel. The second method is seen as being one 
which would be followed in most instances. 



50 



Other Pertinant Data . Information which is relevant to analyz- 
ing a crossing situation or evaluation alternatives, but which is 
not included in the above descriptive categories, should be record- 
ed here. 

k.k.3 Examining Alternatives 

The next step in the need assessment process should be to ex- 
plore various non-structural and structural alternatives to meeting 
the requirements of the crossing situation. 

Non-Structural Solutions . First consideration should be given 
to non-structural solutions. These can be grouped into six categor- 
ies: (1) Status Quo; (2) Traffic Control Strategies; (3) Alterna- 
tive Routes; (k) Alternative Travel Modes; (5) New Technology; and 
(6) Land Use Planning. They are described in further detail subse- 
quently in Chapter 7. Non-structural solutions can be selected 
from one or more of these categories and may be used as the only 
recommended improvements or in combination with structural improve- 
ments, in order to reduce the cost of the latter. Non-structural 
solutions can be low cost or high cost improvements. 

Low Cost Non-Structural Solutions . Each of the six non-struc- 
tural categories have low cost solutions within them and these 
should be considered first. Status quo is essentially a decision 
to do nothing, which may be the final approach adopted, depending 
upon the results of the analysis of other strategies. Relatively 
minor traffic control modifications are a common example of low cost, 
non-structural solutions. Utilization of alternative routes to cir- 
cumvent a barrier may also be a satisfactory low cost solution where 
little or no improvements are necessary to the existing street net- 
work. Alternative travel modes, if requiring only rerouting or re- 
scheduling of existing services, may be an inexpensive solution to 
some crossing problems. 

Document Reasoning . If a low cost, non-structural solution is 
selected, the reasons for its selection should be documented, to- 
gether with the reasons for rejecting other solutions considered. 

Recommended Low Cost, Non-Structural Solutions . Recommended 
low cost non-structural improvements should be described in detail, 
along with preliminary cost estimates. This information is then 
entered into the ranking process so that the priority of the proposed 
improvements can be established. 

Status Quo . The decision to make no improvements at all based 
upon a thorough assessment of alternative methods of solving the pro- 
blem at the potential site is a definite option for short-term as 
well as long-term planning. If this conclusion is reached, the reas- 
oning should be documented and the recommendation made that no modi- 
fications be implemented. 

51 



If neither a low cost, non-structural solution nor maintaining 
the status quo appears desirable at this point, higher cost, non- 
structural alternatives, such as signal izatlon or transit, and 
structural alternatives should be evaluated. 

High Cost, Non-Structural Solutions . Each of the six non-struc- 
tural solution categories have high cost versions. Continuance of 
the status quo may have high cost consequences for impacted travelers, 
for instance, while alternative route utilization may require exten- 
sive upgrading to make it accessable and safe, as another example. 
Each of the six categories should be reviewed and any promising 
possibilities identified. 

Structural Solutions . Construction of a new or retrofitting 
an existing grade separation may prove to be the most effective 
method of providing access across the barrier. Representative 
examples of such strategies are described in detail later in this 
chapter. Preliminary decisions should be made to determine the basic 
type of structure required (whether over- or undercrossing, new or 
retrofit, and so on), using design selection criteria described else- 
where in this report. 

At this stage in the process, one or more high cost, non-struc- 
tural alternatives and one or more potential structural solutions 
will have been selected for further analysis. The process can then 
be continued so as to establish the relative attraction for various 
alternatives at the same site, or to establish the relative priori- 
ties of improvements at a number of different sites. 

k.k.k Mandatory Pre-Cond? tions 

For high cost improvements to be justified, whether structural 
or non-structural, there are two pre-conditions which must be satis- 
fied before these strategies merit further consideration. These are 
permanence of conditions and engineering feasibility. 

Permanence of Conditions . The site conditions requiring a high 
cost alternative and the anticipated service life of the improvement 
must be sufficiently long lasting to justify the expenditure of funds 
involved. 

Engineering Feasibility . The proposed improvement must be feasi- 
ble with regard to satisfying accessibility and engineering design 
cri teria. 

Reject Solution . If one or both mandatory pre-conditions cannot 
be satisfied, then the high cost solutions should be rejected. 

Re-evaluate Alternatives . If the original high cost solutions 
have been rejected, alternatives must be re-evaluated to determine 



52 



if there are any other promising low cost or high cost strategies 
that may be acceptable before concluding that the only acceptable 
course of action is to maintain the status quo. 

k.k.5 Reviewing Warrants and Criteria 

If both mandatory pre-conditions are found to exist, for either 
structural and/or high cost non-structural alternatives, the next 
step is to evaluate the degree to which each solution satisfies 
adopted warrants. The warrants and criteria fall into six categor- 
ies: economic, threshold, system, point rating, policy and politi- 
cal prerogative (community input). A procedure which combines all, 
or elements of all of these areas, appears to be the most reasonable 
method of determining relative need for bicycle and pedestrian facil- 
ities. Each of the warrant and criteria categories should be re- 
viewed and procedures exercised where found to be applicable. 

In order to estimate how well each warrant is satisfied, the 
alternative strategy will need to be detailed to the point where 
various input data (such as cost, for example) can be estimated. 
The process is essentially an iterative one which should be repeat- 
ed as required until the alternative is sufficiently refined or is 
rejected as not being applicable. 

Establ ished Pol icy . Established policies or pre-determined 
guidelines affecting various aspects of non-motorized travel are 
useful tools when assessing facility need. Increased use of policy- 
based decisions will simplify the warrant process. The following 
list are examples of general policies affecting non-motorized travel 
which might be considered: 

• Pedestrian patterns should be maintained across limited 
access roadways and major arterial routes where such patterns 
have been established prior to construction of the roadway. 

• Where pedestrian and/or bicycle facilities exist on the 
approach roadway, they should be continued across the vehicu- 
lar structure. 

• Consideration should be given to a pedestrian/bicycle grade 
separation only when the conditions that require the struc- 
ture are likely to continue indefinitely. 

• Every effort should be made to provide an overcrossinq 
rather than an undercrossing, unless special circumstances 
particularly favorable to an undercrossing exist. 

• Bicyclists should be allowed to utilize shoulders of limit- 
ed access roadways wherever the safety and convenience 
thereon is greater than alternative routes available to 
bicycle travel. 



53 



• All pedestrian facilities should be accessible to the handi- 
capped. 

• Space for pedestrians and bicycles should normally be in- 
cluded in the design of all new highway grade separations. 

• Pedestrian and bicycle facilities should generally be pro- 
vided on both sides of grade separations shared with motor 
vehicles. 

• Space for pedestrians and bicycles should be available on 
all grade separations along designated emergency evacuation 
routes in urban areas. 

Policies are not meant to be followed indiscriminately. When 
specific situations appear not to justify following the directive 
set forth in a policy, then a rationale should be developed for a 
variance to the established policy. The burden of proof, however, 
would then rest on those who believe non-motorized facilities should 
not be provided as stated in the policy. Typically, this procedure 
would involve technical staff presenting professional opinions as to 
why, in that particular instance, the policy should not be applied 
and what alternatives should be considered instead. 

Political Prerogative . Citizen and community representatives 
can provide valuable assistance to planners and designers during the 
planning and design stages of over- and undercrossing projects. 
Public participation is typically solicited and generally takes the 
form of public hearings and advisory committees as means by which 
local preferences can be expressed. Therefore, many of the basic 
questions have already been studied in detail and resolved prior to 
the public hearing. This process allows decision-makers to focus 
their attention on the remaining questions and thereby maximize the 
opportunity to further improve the proposed facility. Community 
input is most effective when provided throughout the planning pro- 
cess, rather than after many of the important decisions have been 
made. 

A specialized form of community input involving the handicapped 
should also be considered. For instance, panels made up of persons 
with varying disabilities were used successfully in this study to 
provide insight into special travel problems. This type of input 
would be very useful in the planning and site evaluation stages of 
future over- and undercrossing projects and make it possible for 
planners and designers to develop facilities more responsive to the 
site specific needs of the handicapped. Wherever possible, local 
handicapped persons should be involved in the process. 

Similarly, bicyclist organizations and jogging clubs can also 
contribute their users perspectives on needs and relative attractive- 
ness of design approaches and details. 

5h 



4.4.6 Establishing Priorities 

Structural and high cost, non-structural solutions assessed in 
the previous step now can be either rejected or relatively ranked, 
depending upon the degree to which they satisfy the warrants and 
criteria. 

Identify the Degree of Satisfaction . Each alternative evaluat- 
ed satisfies a warrant or criteria to a certain degree, The cumu- 
lative result may range from being very positive to very negative. 
The more absolute negative factors, such as those contrary to an 
adopted policy or strongly opposed by the community, may be suffi- 
cient reason to completely reject the alternative. Those alterna- 
tives which do not have a clear reason for rejection are carried 
forward and prioritized. 

Reject Alternative . If an alternative is rejected, the next 
step is to re-evaluate other non-structural and structural solu- 
tions to determine if there are other strategies which hold prom- 
ise. This re-evaluation may lead to other solutions which are not 
rejected and become eligible to be prioritized or the result may 
be that no solution is acceptable and the status quo is retained. 

Priori tize . This process can be used to help select a pre- 
ferred alternative from among the various possible improvements at 
one given site or to help establish the relative priorities of im- 
proving a number of sites competing for limited funds, depending 
upon how well the criteria are satisfied. At this stage in the 
planning process, priority is probably best indicated by broad 
groups (high-medium- low) , rather than by giving a numeric point 
score implying a more rigid sequential priority. Grouping allows 
flexibility and facilitates the project selection and budgeting 
process. Community participation is very useful in establishing 
priorities. The panel of handicapped persons mentioned earlier 
could provide insight as to locations particularly important to 
handicapped accessibility, while other user groups can help in 
identifying those projects which would be particularly beneficial 
to them. 

4.4.7 Implementation Action 

Proposed improvements should then be categorized with respect 
to type of action anticipated for implementation. This includes 
establishing short-term and long-term priorities, as well as noting 
the existance of special opportunities for implementation. 

Short-Term Project . There are generally improvements which 
can be completed within a two-year period. Low cost, non-structural 
solutions, as well as very urgent structural or high cost non- 
structural solutions would often be in this category. The design 
of a future project could also qualify as a short-term priority. 

55 



Long-Term Project . Projects to be implemented within the two 
to five-year range, as well as those in the more distant future, 
can be classified as long-term projects. Expensive projects most 
often will require more time to implement because of funding limita- 
tions and the longer lead time to fulfill approval, coordination 
design and other requirements. There are some instances where 
desired improvements logically hinge upon completion of other pro- 
jects. Therefore, even a relatively inexpensive solution may have 
to be deferred and should therefor be classified as a long-term 
project. 

Special Opportunities . Special opportunities for implementa- 
tion may arise and thereby accelerate the implementation of a pro- 
ject, regardless of its relative priority. Some examples of cir- 
cumstances which may create special opportunities include sudden 
positive changes in funding availability; land developement or re- 
development; construction or rehabilitation of a grade separation; 
construction of any kind which creates a barrier to non-motorized 
travel or catastrophies which damage or collapse existing grade 
separations and which require immediate attention. Special oppor- 
tunities can best be taken advantage of where the planning process 
has already identified the preferred alternative movement, thereby 
enabling timely decisions to be made to include the appropriate 
type of non-motorized facilities. 



CHAPTER 5 

DESIGN SELECTION CRITERIA AND DESIGN CONCEPTS 

5.1 INTRODUCTION 

This chapter describes a series of basic questions on design select- 
ion criteria for which the answers provide guidance in determining whether 
structural or non-structural alternatives are most appropriate. In addi- 
tion, various elements of the system developed to classify new and retro- 
fitted structures is presented and explained. Both design selection 
criteria and design concepts lead directly into the Design Approaches and 
Strategies documented in Chapter 7. 

5.2 DESIGN SELECTION CRITERIA 

Once the decision has been made to provide some sort of crossing 
facility, the next question to be resolved is identification of the most 
appropriate solution. Design selection criteria are defined as those 
measures which help select the preferred basic design type or types from 
among a variety of possible alternatives available at a crossing site. 
It should be kept in mind, however, that over- and undercrossings should 
be considered as parts of existing and future transportation systems, 
and their elements — end conditions, approaches, structure — must also 
be designed as a system. 

Early answers to fundamental questions regarding selection criteria 
are very useful, since they focus design efforts on the most productive 
areas. Fundamental questions to resolve include: 

• Non-Structural versus Structural Solutions 

• Over- and Undercrossing 

• Exclusive or Shared Structure 

• New versus Retrofit Structure 

• One-Si ded versus Two-Sided Facilities 

• Need for Special Features 

Approaches which help answer each of these questions are discussed 
in the following paragraphs: 

5.2.1 Non-Structural versus Structural Solutions 

The first decision which should be made is whether the problem is 
solved best by a non-structural solution or a structural solution. 
Since non-structural solutions can usually be implemented faster and/ 
or at less cost than structural solutions, they should always be con- 
sidered first. Non-structural solutions for non-motorized travelers 
are defined as those solutions which: 



57 



• Utilize existing structures without requiring modifications 
of structural features; or 

• Provide alternative travel routes; or 

• Reduce the need to cross barriers; or 

• Provide alternative travel modes. 

The various types of non-structural solutions are described in 
detail in Chapter 7 of this report, where Design Approaches and Strat- 
egies are presented. 

5.2.2 Over- or Undercrossing 

If it has been decided that a structural solution is appropriate 
to meet the needs of non-motorized travelers, the next decision is 
whether the grade separation should be an overcrossing or an under- 
crossing. In most instances, this is a relatively straightforward 
decision based on such fundamental questions as ... 

• Do site conditions favor an overcrossing or do they favor an 
undercrossing? (See Table 2.) 

• Is there an existing over- or undercrossing which can be shared 
or retrofited? 

• Are there adopted policies favoring over- or undercrossings in 
simi lar situations? 

Answers to these questions should readily resolve the appropriate- 
ness of an overcrossing or undercrossing. 

5.2.3 Exclusive or Shared Structure 

Another early decision to be made is whether the grade separation 
should exclusively serve non-motorized travel or whether it should 
serve both motorized and non-motorized travel. Again, the answers to 
the following provide guidance: 

• Is an existing or planned vehicular structure available? 

• Is there space available on the structure to accommodate non- 
motorized travel? 

• If not, is it feasible to retrofit the structure to create the 
space necessary for non-motorized travel? 

• Are there reasonable alternative routes available for non-motor- 
ized travelers to cross the barriers? 

YES answers favor a shared facility, while if all answers are 
NO, an exclusive bicycle/pedestrian grade separation should be explored, 



5B 



TABLE 2 
Typical Ramp Lengths 
For Overpasses and Underpasses 5 



Description of Structure 


Elevati 


on Change 


Approximate 
One Approach 

8% Grade 


Length of 
Ramp** 

10% Grade 


UNDERPASSES: 










Pedestrian Undercrossing 
beneath public highway 


10-12' 


descent 


140' 


110' 


Pedestrian Underpass 
beneath railroad 


10-14' 


descent 


150' 


125' 


Vehicular Undercrossing, where 
sidewalk follows same grade as 
vehicular roadway rather than 
elevated independent grade 
(15 ft. vehicular clearance) 


18-20' 


descent 


240' 


190' 


Vehicular Underpass under 
railroad, where sidewalk follows 
same grade as vehicular roadway 
rather than independent grade 
(15 ft. vertical clearance) 


19-24' 


descent 


270' 


215' 


OVERPASSES: 










Overpass spanning Interstate 
highway with a 17' vertical 
clearance 


19-21' 


ascent 


250' 


200' 


Overpass spanning public street 
with a 15' vertical clearance 


17-19' 


ascent 


225' 


180' 


Overpass spanning railroad, 
non-electrified, with 23' 
vertical clearance 


27-30' 


ascent 


360' 


285' 


Overpass spanning railroad, 
electrified or requiring pro- 
visions for future electrifica- 
tion, 26' vertical clearance 


30-33' 


ascent 


400' 


315' 


To convert to metric, multiply 


Feet x 0. 


3048. 







Source: De Leuw, Cather & Company. 
* In some marginal cases the choice between an overcrossing or under- 
crossing may depend on the ramp lengths required and the impact of 
such ramps. This table displays the lengths required for a variety 
of elevation changes. 

** Landings not considered, but if used will lengthen the approach 
ramp. 59 



5.2.^ New versus Retrofit Structure 

Several questions should be asked to confirm the need for a new 
or retrofited structure. They are as follows: 

• Is there an existing structure? 

• If yes, is it structurally feasible to modify the existing cross- 
ing to accommodate non-motorized users? 

• is the remaining life of the existing structure sufficiently long 
to amortize the expense of modification? 

If any of the answers to the above questions are NO, then a retro- 
fit solution is either not possible or not practical. If all answers 
are YES, then a retrofit solution should be considered along with new 
structures which appear to be feasible. Ultimately, cost estimates 
may be the single most important deciding factor between new and retro- 
f i ted faci 1 i ties. 

5.2.5 One-Side versus Two-Side Non-Motorized Facilities 

There are often pressures to reduce costs by providing. pedestrian/ 
bicycle facilities on only one side of a structure, regardless of the 
consequences. Two-sided facilities are the preferred design for most 
shared grade separations because of safety reasons. It is very import- 
ant that pedestrians and bicyclists should not needlessly have to 
cross a travelway to use a one-sided facility. However, there are cer- 
tain special circumstances where non-motorized facilities on one side 
may be acceptable. To ascertain such acceptability, the following 
questions should be asked: 

• Does the structure serve one-way traffic? 

• Is a central pathway position feasible? 

• Do al 1 non-motorized travelers use a single, separate pathway on 
both ends of the structure? 

• Is a culvert or tunnel used? 

YES answers indicate a situation where a one-side facility may be 
acceptable. There may also be situations where one-sided non-motorized 
facilities can be tolerated as a temporary solution prior to completion 
of two-sided facilities. 

5.2.6 Special Design Features 

Special design- features may be required to facilitate access and 
enhance use by non-motorized travelers in the presence of certain site 



60 



characteristics. These features are described in the following para- 
graphs, together with the applicable site conditions. 

Rest Areas . These are places where non-motorized users can stop 
and rest. Typically, a rest area is flat or has a flatter grade than 
the adjacent segment. Hand rails and sitting places may also be pro- 
vided. A rest area may be created as a by-product of a specific design. 
For instance, a switch back ramp design has landings each place that 
the ramp changes directions. Other rest areas are especially created. 
Site conditions indicating that a rest area should be considered are: 

Regular use by the handicapped. 

Long ramp (greater than 100 feet) 

Steep ramp (exceeding the 5 percent desirable maximum) 

Limited approach space which may result in steep ramps. 

Connection to a transportation terminal or other high usage area 
where significant numbers of handicapped, elderly or travelers 
carrying bundles can be expected. 

Scenic view opportunities where persons stop for sightseeing. 

Special Signing . These can be very helpful in regulating, warning 
or guiding users along and through a transportation system. Signing 
serves to increase the users 1 degree of confidence, allows persons to 
decide early whether or not to use the route, and serves to avoid sur- 
prises along the way. Site conditions indicating that special signing 
may be needed are as follows: 

Complex crossing situations. 

A large number of infrequent users. 

Regular use by the handicapped. 

A connection to a transportation terminal or other high usage area. 

Scenic view opportunities. 

Elevators/Escalators . Specialized equipment can serve a very use- 
ful purpose in certain situations. Some fundamental access site charac- 
teristics indicating potential use of elevators include: 

Frequent use by the handicapped. 

Connection to transportation terminal or other high usage area. 

Regular access is via stairs or long and/or steep ramps. 

View Screens . These are provided to preserve the privacy of adja- 
cent land uses; such as where residential privacy is infringed upon by 
users of grade separations, for example. 



Gl 



Sound Screens . These are used in areas where high noise levels im- 
pact adjacent land uses. Sometimes view screens can also serve to de- 
crease noise levels. At other times, a grade separation itself may 
functionally serve as a partial sound barrier. A sound barrier is typ- 
ically placed to protect adjacent land uses and they are rarely used to 
reduce sound impact on the users of a grade separation, although this 
is sometimes an additional benefit. 

Wind Screen . This special design feature is sometimes installed 
in extremely windy areas where grade crossing users would be adversely 
affected. View screens and sound screens may also provide some pro- 
tection from the wind. 

Surface Treatments . These are important to assure user stability 
and usability during a variety of weather conditions. Textured pave- 
ment could include brushed surfaces or surfaces with imbedded grit. 
Pavement grooving is another technique used to provide improved tract- 
ion. Open grating has been used successfully to lessen the impact of 
snow accumulation. Site conditions indicating potential use of special 
surface treatments include. 

Regular use by handicapped. 

Steep grades. 

Connection to transportation terminal or other high usage area. 

Snow accumulation. 



5.3 DESIGN CONCEPTS 

As part of the Research and Development phase of this study, methods 
were explored to categorize and classify types of design strategies. A 
classification system was developed for each of the two major categories, 
new projects and retrofit projects. Classifying the project types and 
analysis of the 72 case studies led to the development of initial 
generic prototypical solutions applicable to the majority of crossing 
situations. Further treatment and refinement were directed toward con- 
cepts of non-structural, as well as structural solutions; innovative 
and unusual treatments were also analyzed. A summary of these results 
is presented in this section. 

5.3.1 Crossing Classification Systems 

A classification system was developed to facilitate organization 
and analysis of the case studies assembled early in the study and as 
a base from which to refine prototypical solutions. The 72 case 
studies were first divided into new and retrofit projects. The pro- 
jects were further separated, as follows, in Figure *t. 



62 



NEW PROJECTS 

• Main crossing purpose . 

movement of motor vehicles 

serve bicyclist and pedestrian travel 

- other purposes (carry utilities, etc.) 

• Crossing type . 

- overcrossings (overpass or bridge) 
undercrossing (underpass or tunnel) 

• Motor Vehicle Traffic Characteristics or Length of Structure . 
RETROFIT PROJECTS 

• Si tuation . 

- addition of bicycle and pedestrian facilities where they did 
not previously exist. 

- expanding or upgrading existing bicycle and pedestrian 
faci 1 i ties. 

- widening, expansion, or repair to accommodate additional 
motor vehicles and simultaneously adding bicycle and pedes- 
trian faci 1 i ties. 

- conversion of an existing structure to the exclusive use of 
bicyclists and pedestrian. 

• Crossing type . 

- overcrossing 
undercrossing 

• Solution characteristics . 

type of alteration: cantilever, traffic barrier addition, 
etc. 

type of structure modified: highway bridge, culvert, rail- 
road trestle, etc. 



Figure k. CROSSING CLASSIFICATION SYSTEM 



63 



In developing the classification systems for new and retrofit 
projects, it was found that the kind of barrier crossed — water, road- 
way, railroad, or other — can greatly affect parts of the overall 
structural design and the total cost of a project, but has virtually 
no influence on design strategies for bicycle and pedestrian facilities 
and their categorization. For instance, the operational characteristics 
of non-motorized travel on a bridge over a river or on an overpass over 
a roadway are usually indistinguishable. 

The classification systems developed for new and retrofit projects 
are illustrated in Figures 5 and 6 , respectively. 

5.3.2 Derivation of the Prototypical Design Strategy 

Using both classification systems, it is possible to identify 14 
categories of design types for new projects and 23 for retrofit pro- 
jects. Fortunately, all of these design types need not be considered 
as different design strategies. From the perspective of providing 
facilities for the bicyclist and pedestrian, many structural and cross- 
ing types can be considered to be the same. Further, the design 
strategies for retrofit and new projects act in a complementary manner 
to each other. Particular features, such as placement of traffic bar- 
riers, shown in one strategy are often applicable in another as well. 

Consideration of these factors, plus the desirability of reducing 
the number of design strategies to a more manageable number, resulted 
in the selection of generic prototypical new projects and retrofit 
projects. These solutions are representative of the majority of 
crossing situations encountered and contain both structural and non- 
structural elements. They constitute a sufficiently comprehensive 
display from which an appropriate design for a specific site condition 
can reasily be extracted. Selected examples of these prototypical 
design strategies are included in Chapter 7, Design Approaches and 
Strategies, of this report. 

It should be generally noted that a policy of providing access 
for the handicapped is a principal design consideration responding to 
federal and many state standards, and has been followed in this report. 

Currently, maximum or minimum allowable design standards are 
often applied in practice, whereas use of desirable design standards 
would be preferable. There is almost no conflict in design standards 
for bicyclists, pedestrians and the handicapped if the most desirable 
standards for each group are used, rather than maxima or minima. In 
fact, inclusion of desirable features for one group of non-motorized 
users usually enhances travel for the others as well. In view of 
current operating practices, it must be assumed that bicyclists, 
pedestrians and the handicapped will all use the same facility. 



Gk 



MOTOR VEHICLES GRADE SEPARATION 



Overpass 


or Bridge 


Under 


pass 


Tunne 


1 


TRAFFIC 


TRAFFIC 


TRAFFIC 


CHARACTERISTICS 


CHARACTERISTICS 


CHARACTERISTICS 


. E 


LI] 


, E 





ni 


LU 


k or more 


2 Lanes 


4 or more 


2 Lanes 


Medium or 


Light 


Traffic 


or 


Traffic 


or 


Heavy 


Traffic 


Lanes 

6 
Speeds 


k Lanes 


Lanes 


k Lanes 


Traffic 




Speeds 


Speeds 


Speeds 






over 


35 MPH 


over 


35 MPH 






35 MPH 

& 
Medium to 


or less 


35 MPH 


or less 






Light to 


Medium to 


Light to 






Heavy 


Med i urn 


Heavy 


Med i urn 






Traffic 


Traffic 


Traffic 


Traffic 







BICYCLE/PEDESTRIAN GRADE SEPARATION 



Overpass or Bridge 


Underpass or Tunnel 


LENGTH 

Over 100' 100' or 
* less* 


LENGTH 

m 

Over 100' 100' or 
* less* 



OTHER TYPE (UTILITIES ETC.) GRADE SEPARATION 



Overpass or Bridge 


Underpass or Tunnel 


LENGTH 

O 

Over 150' 150' or 
less 


LENGTH 


Over 100' 100' or 
less 



To convert to Metric Multiply Feet x 0.30^8 and MPH x 1.609 
* Solution illustrated in Chapter 7 

Figure 5. NEW PROJECT-GRADE SEPARATION CLASSIFICATION 



65 



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66 



5.3.3 Non-Structural Solutions 

Non-structural solutions provide a crossing service to non-motor- 
ized users without construction or modification of structural features. 
They may include operational changes to existing structures, providing 
alternative travel routes, removal or reduction of the need to cross 
the barrier, and provision of alternative travel modes. The use of 
non-structural strategies can sometimes provide crossings for bicycl- 
ists, pedestrians, and the handicapped with minimal investments of 
time and money. They should be given priority consideration involving 
crossing problems. Non-structural solutions can be grouped under five 
headings; these are listed below and discussed in detail in Chapter 6. 

• Traffic control strategies 

• Alternative routes 

• Alternative travel modes 

• New technologies 

• Land use planning 

5.3.^ Structural Solutions 

Structural solutions involve construction or removal of physical 
facilities to accommodate bicyclists, pedestrians and the handicapped. 
As already mentioned, there are two major classes of projects, new and 
retrofit. The non-motorized travel way on new projects can be part of 
a bridge, overpass, underpass, or tunnel, whose major purpose is the 
conveyance of motor vehicles, or it can be a separate structure intended 
solely for the use of bicyclists and pedestrians. Bicycle and pedes- 
trian crossings will continue to be primarily built as part of motor 
vehicle crossings because of the cost savings inherent in combined 
facilities and the difficulty of justifying the cost of facilities for 
the exclusive use of non-motorized travelers. Most of the facilities, 
whether on combined or exclusive structures, will be overpasses or 
bridges rather than undercrossings or tunnels. 

Retrofitting involves the addition of facilities to existing 
structures, or the conversion of existing structures to non-motorized 
use. Retrofitting existing structures to create or modify facilities 
for non-motorized users is still relatively rare and is usually under- 
taken in conjunction with other repairs or reconstruction. Designing 
quality of retrofit facilities is usually more difficult than design 
of new projects, since existing conditions sometimes restrict oppor- 
tunities to implement desirable designs. 

New Project Structural Solutions . A major determinant of the 
characteristics of non-motorized facilities is the primary purpose of 
the crossing. While all bicycle and pedestrian facilities should 
adhere to design standards, the construction materials and the physical 
layout of approach and end conditions will vary depending upon whether 
the crossing primarily carries motor vehicles, bicycles and pedes- 
trians, or uti 1 i ties. 

67 



Structures Shared with Motor Vehicles . In some instances, space 
must be allocated on the structure and approach roadway cross- 
sections to enhance safety and ease of operations for bicycle and 
pedestrian travel. This could involve a wider deck on a bridge 
or overpass, or additional shoulder area in an underpass. For an 
underpass, a separated path or sidewalk is also an alternative. 

Physical barriers, such as New Jersey barriers or vehicle guardrail, 
should be considered where traffic is heavy or operates at high 
speed and the bicycle and pedestrian travel way is adjacent to that 
for motor vehicles. Vertical or horizontal separation of non- 
motorized and vehicular ways is also a possibility, particularly 
on approaches. Where motor vehicle traffic volumes are relatively 
light and slower, signing and striping may provide adequate pro- 
tection for the non-motorized user. 

Difficulties for the bicyclist and pedestrian can occur at the 
ends of the crossing where the existing sidewalk, bikeway and 
street system begin, and where vehicular traffic may have to be 
crossed in order to proceed in a desired direction. Special 
attention must be paid to signing, striping and signal ization to 
insure safe operating conditions; especially where end conditions 
require complicated movements to be made by the non-motorized 
traveler. 

Structures for Bicyclists and Pedestrians Only or Shared with 
Uti 1 i ties . Opportunities for providing a good crossing for the 
non-motorized traveler are greatly enhanced when motor vehicles 
are eliminated from design considerations. In such instances, the 
length of the structure then exerts the most significant influence 
on the design by generally eliminating use of some materials, such 
as wood, for longer span overcrossings. However, bridges, under- 
passes, and tunnels for bicyclists and pedestrians are usually 
constructed using the same materials and construction techniques 
as for motor vehicle structures. 

Advantages in both aesthetics and cost can be achieved by com- 
bining utility crossings with those for bicycles and pedestrians. 
The utilities can often be fastened below or alongside the bridge 
deck. The disadvantage may be that the optimum crossing point 
for the utility and for bicycle and pedestrian travel may not be 
coincident. 

End conditions for the solely non-motorized facility can often 
be complex when users rejoin the existing street and pedestrian 
travel system. In addition, posts, gates, or other barriers, 
may be required to prohibit use of the facility by motor vehicles. 
Some of these barriers present operations hazards to bicyclists 
and the handicapped as well, however. 



68 



Retrofit Structural Solutions . Where a retrofit solution adds 
bicycle and pedestrian facilities to a structure shared with motor 
vehicles, there are three basic methods of providing space. These are: 
reallocation of existing space to the non-motorized traveler; construc- 
tion of additional space; or some combination of these. 

As was the case with new construction, a degree of separation must 
be provided between motor vehicles and bicyclists and pedestrians. 
Separation can be accomplished by addition of a physical barrier if 
traffic is heavy or high speed, or by striping and signing if motor 
vehicles constitute less of a hazard. There are some instances where 
an unmarked shoulder of adequate width is satisfactory. 

To gain additional space on overpasses or bridges, it may be 
possible to cantilever additional decking from the existing structure 
or to construct an adjacent fully or partially self-supported struc- 
ture. Either method could provide all of the required space, or could 
be combined with some deck space from the existing overcrossing. 

Underpass roadway sections may have to be modified by excavation 
of adjacent cross slopes and possibly construction of retaining walls 
in order to gain additional space. 

Another form of retrofiting is the total conversion of an exist- 
ing structure to bicycle and pedestrian use. Abandoned or greatly 
underutilized railroad trestles, highway bridges, and large culverts 
are prime candidates for this type of changeover. 

5.3.5 Innovative and Unusual Treatments 

Innovation is defined as something new or different or changes 
in anything established. Innovation ranges from minor modifications 
to direction-setting technological breakthroughs. In regard to over- 
and undercrossings, innovation is applicable to design strategies, 
design review, project implementation, maintenance, and user educa- 
tion. 

At present, there appears to be no anticipated major technologi- 
cal breakthrough that will drastically change development of struc- 
tures for non-motorized facilities. However, there are a number of 
modifications or enhancements of existing methodology and procedures 
which can be considered innovative. While unusual crossing treatments 
and applications of new technologies may represent satisfactory 
design solutions in only very limited instances, they still should 
be kept in mind in view of their potential benefits and/or lower cost. 
These are discussed further in Chapter 6 under the following four 
headings: 

• Unusual locations and facility configurations 

• Recycled materials 

• Construction techniques 

• Alternative methods of conveyance 

69 



CHAPTER 6 

FIELD EVALUATIONS 

6.1 INTRODUCTION 

A number of site investigations were carried out in the course of 
this study, as described earlier in Chapter 2. The basic purpose of 
this activity was to evaluate some of the promising new designs, design 
modifications and non-structural solutions previously identified among 
the 72 case study examples of current practice cited earlier. The 
results of these evaluations are summarized in this chapter. These 
evaluations, together with the design strategies discussed in Chapter 7, 
provide the reader with descriptions of a number of good treatments and 
suggested design features, both conventional and innovative, for accom- 
modating non-motorized travellers on over- and undercrossings. The 
discussion below also includes perceived deficiencies, as well as the 
favorable aspects of the various crossings studied. 

The field work involved comprehensive evaluations at six selected 
sites; visits to three locations in California and four in Florida, 
where the reactions of a panel made up of persons with a variety of 
physical disabilities were obtained. In addition, team members visited, 
photographed and informally observed almost 200 other grade separations 
throughout the duration of the study. 



6.2 COMPREHENSIVE EVALUATION SITES 

The locations and types of facilities selected by the study team 
in consultation with FHWA staff for comprehensive evaluation were: 

Palo Alto, California . An exclusive bicycle and pedestrian bridge 
with an approach canti levered along a drainage canal was selected as the 
site of the pilot study carried out to test and refine the site evalua- 
tion procedures. 

Sunnyvale, California . A new exclusive pedestrian and bicycle 
overcrossing of a busy freeway at this location was chosen as a repre- 
sentative example of a facility with the latest treatments intended to 
facilitate use by the handicapped. 

Eugene, Oregon . Two structures were evaluated in detail in Eugene. 
One location combines a bicycle and pedestrian undercrossing of the 
Southern Pacific Railroad with a nearby bicycle and pedestrian bridge 
over the Willamette River. The second facility is a retrofitted direct 
ramp connection for bicyclists and pedestrians only, leading from the 
sidewalk along one side of a four-lane highway bridge to a park and 
riverside trail system. 

70 



Hampton, New Hampshire . A retrofitted bicycle and pedestrian 
facility can ti levered from a highway bridge over a railroad was analyzed 
at this location. 

Route 183, Randolph Road, Maryland . This site was chosen for its 
modified box culvert featuring an elevated pathway capable of use during 
most of the year as an underpass, except when it becomes innundated 
during periods of high water. 

Austin, Texas . Special off-street facilities have been constructed 
to accommodate bicycle and pedestrian travel through a complex inter- 
change made up of one-way streets and ramps. 

Following a discussion of general observations and findings drawn 
from composite results of the six studies, individual design character- 
istics and construction costs of each of the six sites are described 
below. More detailed descriptions of each site is contained in the 
Appendix. 



6.3 GENERAL OBSERVATIONS 

A number of especially good design features were noted during the 
evaluation visits and these are indicated in Table 3. 

The deficiencies which were observed fell into three general areas: 
signs, signals and markings; maintenance; and design features. The 
major findings in each of these areas are summarized below. 

6.3.1 Deficiency in Signs, Signals and Markings 

By far the most common deficiency of the sites visited pertained to 
a general lack of guide and directional signing facilitating travel by 
bicyclists and pedestrians. The next most common deficiency related to 
signing was lack of proper horizontal and/or vertical clearance between 
the sign or sign post and the pathway edge. Deficiencies and problems 
identified at one or more of the six evaluation sites can be summarized 
as follows: 

Lack of guide and directional signs causes confusion. 

Lack of regulatory signing at beginning of pathway to inform 

bicyclists and pedestrians where usage is mandatory. 

Improper signing which is either unclear or inappropriate. 

Lack of additional advance warning signs where needed, such as at 

sharp curves, overhead clearance restrictions and flooding conditions 

Raised pavement markers utilized to separate vehicular traffic from 

bike lane users, whether regular or oversized, create a potential 

hazard to bicyclists who may need to cross or travel where markers 

are placed. 



71 



Table 3« Site Evaluation 
Especially Good Features 



Feature 


Palo 
Alto 


Sunny- 
vale 


Eugene 


Hampton 


Mary- 
land 


Austin 


Early and/or continuing 
planning 


X 


X 


X 


X 


X 


X 


Rest areas 




X 


X 






X 


Uniform treatment on 
several structures 












X 


Path widening at curves 






X 






X 


Pathway takes advantage of 
topo and surroundings 


X 




X 




X 


X 


Added lighting 












X 


Took advantage of existing 
street 1 ighting 


X 












Aesthetic use of wood 


X 










X 


High qual i ty , sturdy, 
graspable handrail 




X 




X 


X 




Bolt treatment to cover 
exposed ends 








X 






Treated decking solidly 
attached to structure 








X 






Heavy broom finish on 
walk surface 






X 








New Jersey barrier separation 
from traffic 






X 








Selective placement of guide 
and directional signs 


X 




X 








Bike lane transition 
weaving section 






X 








Rest areas off pathway 




X 


X 






X 


Edge stripe 






X 








Centerline stripe helps night- 
time vis ibi 1 i ty 






X 








Continuous graspable handrail 




X 










Recessed 1 ighting 




X 










Rubberized joint connection 




X 










View screen 


X 


X 











72 



Lack of ref lectorization or other delineation of bridge columns 
or utility poles close to the pathway. 

Signs placed too close to pathway edge thus restricting either 
horizontal and/or vertical clearance. 

Edge striping or centerline striping which is lacking where the 
pathway curves, or is subject to congestion. Striping has also 
been found helpful to guide bicyclists riding at night through 
remote and unlit areas. 

Lack of crosswalk delineation at ramps and end conditions is some- 
times a disadvantage to a non-motorized traveler. 

Lack or improper placement of pedestrian signals at signalized inter- 
sections creates crossing problems for bicyclists and pedestrians. 
Lack of PED or BIKE XING advance warning signs at pathway crossings. 
Lack of signing or marking to identify the location of special 
rest areas. 

Lack of striping to delineate the approach to a barrier post in- 
tentionally placed in the pathway to prohibit motor vehicle access. 

6.3.2 Deficiency in Maintenance 

Maintenance is a continuing necessity which, if not properly per- 
formed, can decrease the effectiveness and attractiveness of even the 
best design. While some degree of maintenance must always be performed, 
proper design can minimize the magnitude of maintenance effort and costs 
required. Most of the maintenance deficiencies observed at the site 
evaluation locations were related to debris or vegetation on the path- 
way. Most of these were impediments rather than hazards. However, left 
unattended, an impediment can become a hazard or a barrier to travel. 
Some major maintenance deficiencies observed during the field evalua- 
tions are listed below. 

Glass, sand and miscellaneous debris deposited in bike lanes or 
shoulder areas utilized by bicyclists and pedestrians. 
Grass clippings on pathway creating the potential for slippery 
spots on the pavement. 

Weeds and grass overgrowing the pathway; varying from localized 
intrusion to long stretches of overgrowth. 
Tree branches overhanging pathway. 

A hazardous intrusion penetrated pathway space. (For example, at 
one location a metal anchor for a utility pole guy wire was bent 
into the pathway.) 

Debris on pathway from construction or maintenance operations. 
Sediment deposited on the pathway as a result of flooding. In some 
cases this is a seasonal event (as with pathways sharing culverts) 
and in other cases it occurs only during major flooding. 
Creek erosion of the pathway. 

Pathway shared with horses thereby requiring more frequent main- 
tenance to remove droppings. 
Lighting which has burned out or which has been vandalized. 



73 



6.3.3 Deficiency in Design Features 

Design features identified as deficiencies during the site evalua- 
tions typically involved features which were incomplete and can be sub- 
divided into three categories: Alignment and Clearances; Sight Distance 
and Pavement Quality; and Appurtenances. The incidence of notable 
design error was low. Identified deficiencies and some desirable prac- 
tices include the following: 

Alignment and Clearances 

Pathway alignment which passes too close to a horizontal obstruc- 
tion, especially where an alternative alignment is available. 
Locations where there are deficient or low and variable vertical 
clearances. 

Inadequate maneuvering space at the intersection of a new pathway 
and existing sidewalk. This may require that the existing facil- 
ity be widened at least for a transition distance in the vicinity 
of the intersection. 

Alignments which promote the development of major or minor short 
cut usage. A typical example would be a looping alignment where 
a straighter, more direct route is available. 

Pathway alignments passing areas or localized points where exist- 
ing features significantly contribute to the maintenance require- 
ments. An example would be fruit trees or shrubs which seasonally 
deposit heavy concentrations of fruits and berries onto the path- 
way surface. 

Termination of construction at the exact limit of one agency's 
jurisdiction without regard for site characteristics can result 
in problems. One case observed left unsolved the erosion of a 
creek bank which, over time, would encroach upon the pathway 
extension. As a consequence, future construction may be more 
difficult and costly than if the extension was completed at least 
past the critical creek area, as part of the original project. 
Additional bridge widening was needed to conform with the approa- 
ches and to facilitate shared bicycle and pedestrian usage, but 
was not provided. 

Steep grades at localized points which occur where the new project 
transitions to the existing condition. While these probably do 
not show on the plans and may be a solution of opportunity taken 
during construction, the effect can detract from the usability 
of an otherwise satisfactory over- or undercrossing. 

Sight Distance and Pavement Quality 

Landscaping is often the source of sight distance restrictions 
and extraordinary maintenance requirements. Care should be taken 
to select plantings which do not require frequent maintenance and 
to keep lines of sight free of obstructions. A quick review of 
the plans with regard to sight distance should identify poten- 
tial problem areas. 

7^ 



Wooden planking Is susceptible to warping and this may detract 
from an otherwise acceptable facility. Designs should consider 
fastening each plank securely at each end, as well as at one or 
more places in between. A distance of two to three feet (0.6-0.9M) 
between fastening points on the plank appeared to be effective 
at those sites evaluated in the field. 

Pavement subsidence due to erosion or insufficient subbase strength 
significantly decreases the pathway quality and creates a hazardous 
condi tion. 

Pathways are susceptible to flooding such as those sharing culverts 
with creeks, did not have designated alternative routes to serve 
users during periods of high water. 

Drainage problems which result in water flowing across the path- 
way surface. 

Reverse super-elevation is a design error with respect to bicycle 
usage. The case observed was apparently used to facilitate sur- 
face drainage. 



Appurtenances 



Transition from an off-street pathway to a parallel street requires 
relatively long curb cuts which, if underestimated, tend to pinch 
the entrance angle. 

Existing sidewalks serving as major access to an over- or under- 
crossing often do not have curb cuts. If they do, placement is 
typically random so as not to provide an effective, continuous 
access route for persons using wheelchairs. 

Lack of fencing along a pathway where a steep embankment slope 
exists close to the edge of the travel surface. 

Lack of fencing or barriers where needed to separate the sidewalk 
users from vehicular traffic. This serves the dual purpose of 
being a safety feature to prevent sidewalk users from falling 
into the street, as well as a splash guard to prevent road wash 
from being sprayed over the sidewalk. 

The New Jersey type concrete barrier to protect sidewalk users 
terminated just before the point where other pathways intersect. 
Handrails had unnecessary gaps in them, such as may occur between 
the approach and the structure or at locations where a future 
light pole is planned but has not been installed. Many such 
problems can be avoided during design, while others may require 
a retrofit treatment to close a gap permanently or temporarily 
until all facilities are completed. 

Lack of view screens to a crossing facility to protect the privacy 
of adjacent properties. However, care must be taken that such 
screening does not restrict sight distance along the pathway. 
Difficult nighttime pathway travel because of darkness or glare 
from approaching traffic where lighting, delineation and new 
screen were not used. 



75 



Lack of lighting on many over-crossings, as well as in undercross- 
ings. Lighting is often installed only on the structure, while 
there are locations on the approach or along other portions of the 
bikeway/pedestrianway system where lighting deficiencies signifi- 
cantly reduce the attractiveness and safety of the facility. 
Restrictive devices at entrances to pathway facilities which dis- 
advantaged legitimate pathway users. Problems include devices 
which were not clearly visible to both day and nightime users; 
lack of advance warning signs; lack of signing designations; 
restricted and prohibited users; and "negotiation zone" through 
the restrictive device, were on a slope rather than level. That 
is, uphill and downhill travel characteristics should not com- 
plicate the users ability to safely and efficiently pass through 
the restrictive device. Common devices include closely spaced 
posts or fencing which requires users to travel in a "Z" pattern 
through a narrowed space. 



6.4 GENERAL FINDINGS 

6.4. 1 User Counts 

Counts were made of persons using each of the facilities observed 
during the site evaluations. Counts varied in duration from one-half 
hour long segments to continuous recording throughout the day, and are 
summarized in Table 4. 



Table 4. Site Evaluation 





User Count 


Summary 










User Type 


Palo 
Alto 


Sunny- 
vale 


Eugene 
Ferry SPRR 


Hampton 


Austin 


Mary- 
land 


Pedestrian 


10 


67 


150 


362 


2 


55 





Bicycl ist 


53 


66 


201 


180 


3 


56 





Total Persons 


63 


133 


351 


542 


5 


111 





Child (0-12) 


- 


30% 


- 


- 


- 


1% 





Teen (13-18) 


30% 


49% 


10% 


2% 


60% 


40% 





Young Adult 


kn 


in 


66% 


72% 


20% 


49% 





(19-25) 
















Adult (26-59) 


27% 


12% 


17% 


26% 


20% 


10% 





Senior (over 59) 


2% 


1% 


7% 


0% 


0% 


0% 





Total Percent 


100% 


100% 


100% 


100% 


100% 


100% 





Hours of 
Observation 


1.5 


8 


9-5 


9.5 


4 


5.5 


3 



76 



A total of 1,205 over- and undercrossing users were observed during 
the site evaluation studies. Of these, 559 rode bicycles and 646 were 
pedestrians (persons walking or jogging). Only one handicapped user was 
observed at the six field sites. However, supplemental evaluation 
studies, which featured site visits by individuals with a variety of 
physical handicaps were also conducted in California and Florida as a 
part of this study and results are also summarized later in this report. 

6.4.2 Direction of Travel 



The direction of travel is only meaningful on a site-by-site basis, 
Typically, directional splits ranged from 45/55 to 50/50. 

With regard to wrong way travel, two sites had restrictions. One 
was signed as one-way for bicyclists and the other was implied since 
the end condition was a one-way street. There was some wrong way rid- 
ing observed at both locations, probably because the alternative route 
required a significant detour in terms of both time and distance. 

6.4.3 User Position 

There was a strong tendency for pathway users to travel in the 
central portion of a straight path. This was evident on 4 foot (1.2M) 
wide pathways, as well as for 12 foot (3.7M) wide paths. 

On curves, the travel zone shifted toward the inside of the curve. 
The shift became more pronounced as the curve became sharper. For 
example, the distance from the edge of pavement for an 8 foot (2.4M) 
wide path to the edge of the travel zone was 2 feet 6 inches (0.8m) on 
the straight away; 1 foot 6 inches (0.5,) on the inside edge of a 
slight curve, and 6 inches (0.2M) on a sharp curve. These relation- 
ships are portrayed in Figure 7. 

With the exception of several persons on the narrow sidewalk of 
the Ferry Street Bridge in Eugene, Oregon, no one was seen using a 
handrail. The persons seen grasping the handrail were using it to 
steady themselves while they were being passed by someone in the 
opposite direction. 

6.4.4 Handicapped Features 

Three sites had special rest areas on or along the pathway or on 
the structure. No one was seen stopping at the rest areas located on 
a grade. The only observed rest area usage in Eugene, Oregon, where 
non-handicapped persons stopped to enjoy the view from the Autzen, 
and Greenway bicycle and pedestrian bridges crossing the Willamette 
River. 



77 



"T 



2.5'(0.8m) 



Stra ightaway 



Primary Travel Zone 3. 1 (0.9m) 



2.5'(0.8m) 



8' (2. Am) 



SI ight Curve 




Sharp Curve 



>/ma 




Figure 7. USER POSITION ON PATHWAY 



78 



6.4.5 Travel Behavior 

As near as could be determined, nearly all of the 1,205 over- and 
undercrossing users observed during the site evaluation studies appear- 
ed to be regular users. However, at least two sites served other users 
at different periods of the year. For instance, football spectators in 
Eugene, Oregon, use the SPRR underpass and Autzen Bridge on their way 
to Autzen Stadium. In Hampton, New Hampshire, summer months bring a 
flood of tourist activity, with an associated increase in bicycle and 
pedestrian travel. 

6.5.6 Short Cut Routes 

Short cut routes were observed at four of the six site evaluation 
locations. Typically, short cuts truncated looping approach alignments 
where the user could clearly see a time and distance savings. Most of 
the alternate routes were relatively short and served the approach to 
the structure. None of the routes seemed to be illogical. Time sav- 
ings ranged from several seconds by cutting a corner between inter- 
secting sidewalks to several minutes through an interchange area. 

6.4.7 Noise Qual 1 ties 

With the exception of where loose or warped wooden planking exist- 
ed, observed user noise levels were low. However, this observation 
may be different for the Ahwanee Overpass in Sunnyvale, California, 
during school arrival and dismissal time when high concentrations of 
students are using the facility. The site evaluation was conducted 
in July when school was not in session. 

The ambient noise levels ranged from low to high depending upon 
the volumes of traffic or, in the case of the underpass in Eugene, the 
presence of a moving train. The noise appeared to be most noticeable 
at the Ahwanee overcrossing as a result of traffic on Freeway 101. 
Here, it was interesting to note that during the peak period traffic 
congestion of the freeway resulted in slow moving or stop and go 
travel. During these periods the ambient sound level, even though 
still high, was considerably diminished. 

There were no sites where high noise level appeared to discourage 
bicycle and pedestrian travel. The Autzen and the Greenway bicycle 
and pedestrian bridges in Eugene, Oregon, were facilities where per- 
sons actually come to listen to "noise" — the noise of the Willamette 
River flowing beneath the structure. 

6.4.8 Structural Stability 

All of the structures reviewed during the site evaluation studies 
were basically well-constructed and gave bicyclists and pedestrians 
the feeling of stability. The only exception to this was where wooden 

79 



deck planks were loose or warped and one location where the fencing on 
the approach did not appear to be as strong as fencing used elsewhere 
on the facility. A jump test produced, at most, a slight vibration. 
However, joggers in cadence created rhythmic vibrations which could be 
felt but not to the point where the bridge appeared less stable. 

6.4.9 Design Elements 

The field study focused attention on specific elements and in so 
doing helped the evaluators become more aware of deficiencies which 
may not have been identified by a less detailed inspection. Comments 
applicable to some of the more important design elements are presented 
below. 

1. Grades 

Grades along the pathway facilities typically did not exceed 8.33 
percent. However, significantly higher grades were measured at 
localized points. At one facility the short ramps transitioning 
to the existing conditions had grades of 12 to 27 percent. Simi- 
lar problems occurred at other sites where transitions to exist- 
ing conditions or rest areas resulted in higher grades than 
specified on the design plans. 

This shows that more care needs to be taken in plan review to 
identify areas of potential problems and to specifically detail 
design criteria. In addition, construction engineers must be 
made aware of the problem so field alterations do not result in 
facilities which impede or prevent certain persons from using the 
route. 

2. Cross Slopes 

Cross slopes ranged from 0-5.2 percent with most being about two 
percent. In one instance, a reverse super-elevation was built 
around a curve which facilitated drainage but which created a 
hazard for pathway users, particularly bicyclists. A two per- 
cent cross slope is commonly used to facilitate drainage. 

3. Handrail 

Handrails varied from 2 feet 8 inches to k feet 1 inch (0.8-1.2M) 
high with 3 feet to 3 feet 6 inches (0.9-1.1M) being most fre- 
quent. Handrail heights of 33 - 36 inches (0.3M) is considered as 
being compatible with the needs of the handicapped (61). 



80 



4. Fencing 

Fencing varied in height between 3 feet 5 inches and 8 feet 9 
inches (1.1M and 2.7M). Some of the fencing was associated with a 
separate handrail and at other times there was only fencing with- 
out handrailing. Several locations along the approach pathway 
were identified as being in need of fencing to protect users from 
steep slopes. Fencing compatible with bicycle travel is a minimum 
of 4.5 feet high (1.4M). 

5. Pathway Width 

Pathway widths ranged from 4 feet to 12 feet 6 inches (1.2 to 3.8m) 
with 7 feet 4 inches to 8 feet 5 inches (2.2 to 2.6M) being the 
most common. The narrower widths did not readily accommodate two- 
way travel, while the 8 foot (2.4M) widths appeared to be quite 
usable. Four feet (4.3M) is commonly considered the minimum width 
for a one-way path, with 8 feet (2.4M) being the minimum for a 
two-way path (48, 51). The 12 foot (3.7M) widths were noticeably 
spacious at the volume levels observed and allowed much more 
flexibility for traveling in groups or passing other users. 

6. Overhead Clearance 

Two sites had places where the overhead clearance was 8 feet (2.4M) 
or less. Overhead clearances of 8 feet (2.4M) or more are pre- 
ferred. In one place it was created by a bridge support and the 
restriction was signed. The other location was in a culvert where 
the vertical clearance was further reduced by silt deposit on the 
pathway surface during high water. Here the vertical clearance 
was variable and unpredictable. 

6.4.10 Trip Generation 

Elementary and high schools reasonably close to the facility in- 
creased its potential usage. This was particularly true if the loca- 
tion was such that students, could conveniently use the structure. The 
proximity of a university is a significant source of users, particu- 
larly where the structure provides access to a bikeway or pedestrian 
pathway system which facilitates jogging and recreation trips as well 
as utilitarian travel. Linkage to a greenway trail system with varied 
destinations (such as exists along the Willamette River in Eugene, 
Oregon, or along Town Lake in Austin, Texas) is a definite attraction. 
This allows users to select the length of travel as well as the scenery 
that fits their mood. 

Proximity of residential housing and shopping were other factors 
which were noticeable factors in trip generations. Employment centers, 
particularly where the structure offered a significant time savings 
for bicycle and pedestrian travel, was another factor influencing the 
demand. 

81 



Special events, such as the football games near the Autzen Bridge 
in Eugene, Oregon, or seasonable influxes of tourists as experienced 
in Hampton, New Hampshire, created significant demand for non-motorized 
facilities during specific time periods. 

Each site was evaluated with regard to the presence of various 
trip generation characteristics (see Figure 8). The relative potential, 
high or low, for future non-motorized travel was also estimated by 
identifying the possible changes in land use that could significantly 
increase or decrease non-motorized travel compared to the existing 
situation. Land use categories that were explored included residential 
development; new, enlarging or closing of schools; employment centers; 
recreational opportunities, or a combination of uses. 

The trip generation factors which were most evident at the site 
evaluation locations are summarized in Table 5. 

Table 5. Site Evaluation 
Bicycle and Pedestrian Trip Generators 



Significant Trip 








LOCATIONS 






Palo 


Sunny- 






Mary- 




Generators 


Alto 


vale 


Eugene 


Hampton 


land 


Austin 


High School 




X 








X 


Col lege Students 


X 




X 








and Faculty 














University Housing 












X 


Regional Park 




X 








X 


Neighborhood Park 




X 








X 


Reg i ona 1 G reenway 






X 




X 


X 


Corridor 














Work 


X 




X 


X 






Residential 


X 


X 




X 






Tou r i s t 








X 






Football Stadium 






X 








Community Center 




X 










Regional Shopping 


X 












Center 














Local Shopping 


X 













82 



Type of Barrier 



Desire Line Fit 



Water 
H i ghway 
Mountains 
Canyon 
Land Use 
Rai iroad 

Crossing Opportunities 

Point Only 

No restrictions 

Closely spaced alternative 

Distance to Alternate Route 



< 1000 feet 


( 305 metres) 


1000 feet 


( 305 metres) 


2000 feet 


( 610 metres) 


3000 feet 


( 91^ metres) 


4000 feet 


(1219 metres) 


5000 feet 


(1524 metres) 


> 5000 feet 


(1524 metres) 


Anticipated 


Use 


Local (Neighborhood) 


Regional 




Link in Bikeway/Ped Plan 


Yes 




No 




User Volume 





High > 200/day 
Med 50-200/day 

Low < 50/day 

Permanency of Demand 

Stable 

Likely Increase 

Likely Decrease 



Along It 
Slightly Removed 
Remote 

Topography 

Flat 
Rol 1 ing 
Hilly ' 

Land Use 

Residential 

Commercial 

Industrial 

Institutional 

Recreational (Park) 

Open 

Other 

Schools 



Elementary School 

JHS 

HS 

Col lege 

None 

Shopping Center 

Local 

Neighborhood 
Regional 
None 

Special Considerations 

Bus Stop 
Parking Lot 
Sports Complex 
Other 
None 



Figure 8. TRIP GENERATION CHARACTERISTICS - FIELD EVALUATION FORM 



83 



6.5 HANDICAPPED USER EVALUATION 

Facilities at each of the six site evaluation locations just des- 
cribed were reviewed with regard to their ability to accommodate all 
non-motorized users, including the handicapped. However, the study team 
also conducted special studies where handicapped travellers actually 
helped to evaluate grade separations in the field. Persons from the 
Center for Independent Living in Berkeley, California, formed the handi- 
capped panel which reviewed structures in California while volunteers 
from various active handicapped groups in the Miami area participated 
in the Florida evaluations. 

Selection of the handicapped panel was based on the desire to 
have persons of varied disabilities conduct the evaluations. The range 
of participant disabilities included: 

• Wheelchai rbound (electric and manual wheelchairs) 

• Leg braces, canes, crutches 

• Walker with wheels 

• Limited stamina 

• Blind 

The general study approach of evaluating crossing treatments in- 
volved the use of a team leader and a panel of disabled persons partici- 
pating in the discussions and on-site evaluations. Much of the literature 
and standards reviewed were found to be based on judgements of the non- 
disabled or perceptions of persons with only one type of disability. 
Guidelines for treatments have generally not been based on empirical 
evaluation of behavior on facilities. The technique used in this study 
provided for a greater variety of viewpoints which, it is felt, better 
reflects the heterogeneous composition of the handicapped community 
with its diverse characteristics and needs. 



The sites for the field evaluation of facilities for the handicapped 
were chosen after discussions with state highway officials and the panelists 
and after preliminary visits by study team members. Observation sites were 
selected in the San Francisco Bay, and Miami, Florida areas to provide for 
a variety of recent designs of crossings with and without special provisions 
for the handicapped. Further, the sites were chosen so as to encompass 
a variety of situations likely to be commonly encountered by handicapped 
users (6, 7). 

Each on-site investigation involved traversing a facility and its 
approaches by the panel, then on-site administration of a set of choice 
response and open-ended questions about experience using the facility, 
followed by later more general discussion among panelists and project 
staff about the site. At each of the sites, photographs were taken to 
illustrate user behavior and major findings. Analysis of results by pro- 
ject staff followed. 



6.5.1 San Francisco Bay Area Sites 

The three sites selected in the Bay Area included two exclusive 
pedestrian overpasses and one overpass shared with motor vehicles. All 
three structures provide access across a freeway. Various site details 
are listed in Table 6. Also see photographs, Figure 9. 

The Milbrae Avenue overcross ing, a highway bridge with sidewalks 
within a freeway interchange, was regarded by the handicapped panelists 
as being a hostile environment for pedestrians and particularly the 
handicapped. While curb cuts provided accessibility according to early 
1977 standards, crossing interchange ramps serving high speed traffic at 
unmarked locations was considered a major disincentive to non-motorized 
travel. Other findings from this evaluation are included in Section 6.5.3 
below. 

The pedestrian overcross ing at Mount Diablo Avenue is about half the 
length of the Milbrae Avenue structure and connects two residential neigh- 
borhoods. The structure is not new and is accessed by two solid core con- 
crete spiral ramps. In general, the panel concluded from on-site evalua- 
tion that spiral approaches are acceptible if designed properly. Most 
problems for handicapped travelers at this site pertained to walkway cross 
slope and sight distance restrictions created by the solid core supporting 
the spiral ramps. Again, see Section 6.5.3 for additional findings. 

The Ahwanee Avenue pedestrian overcrossing includes some of the 
latest design elements intended to facilitate travel by handicapped 
persons. These included continuous handrail on approaches as well as 
the structure and level rest areas on and off the pathway. Maximum ramp 
slope was designed to not exceed 8.33 percent. In general, handicapped 
panel members were favorably impressed with this facility and concluded 
that it came close to meeting the needs of the handicapped. The only 
major problem encountered was where a maze-like barrier had been installed 
near the bottom of each ramp to discourage speeding bicyclists and skate 
boarders. Problems for handicapped persons passing through the maze re- 
lated to narrow clearances, location on a slope thereby making wheelchair 
manuevers more difficult, and a confusing route for blind persons to 
negotiate. 

6.5.2 Miami, Florida Area Sites 

The four sites selected in the Miami, Florida area were all exclu- 
sive pedestrian/bicycle facilities. Two of the structures spanned a 
freeway; one bridge crossed a major arterial and canal and the fourth 
bridge simply provided access across a canal. The site characteristics 
are summarized in Table 7 and photographs can be seen in Figures 10 and 11. 

The pedestrian bridge north of Sample Road in Pompano Beach connected 
a residential area to an elementary school on the other side of Interstate 
Route 95> The structure had spiral ramps leading to level structure. 



85 



Table 6. California Overcrossings 
Evaluated by Handicapped User Panel 



Site Specifics 




Overcrossing Locations 






MM Ibrae Avenue 
Mi librae 


Mt. Diablo Avenue 
San Mateo 


Awanhee Avenue 
Sunnyvale 


Access ibi 1 i ty 










Pedestrians 
Bicycles 
Motor Vehicles 




Yes 
Yes 
Yes 


Yes 
Yes 
No 


Yes 
Yes 
No 


Surrounding Land Uses 










Multi-unit residen- 
tial 

Single- unit residen- 
tial 

Commercial 

Industrial 

Open Space 


Yes 

No 
Yes 
No 
Yes 


Yes 

Yes 
No 
No 
No 


No 

Yes 
No 
No 
No 


Adjacent Major Activi 
Centers 


ty 


None 


None 


School, Park 


Date of Faci 1 i ty 
Construction 




1964 (curb cuts 1976) 


1953 


1977 


End Conditions 




k- lane signal ized 
streets with sidewalks 
on one side 


2-lane residential 
streets 


2-lane residential 
streets 


Approach Conditions 




Sidewalks on one side 
with abrupt dropoffs 
over 10' ; pathway 
crosses high speed 
freeway ramps 


Spiral ramps 


Swi tchback ramps 


Structural Conditions 




Sidewalks on one side 
with abrupt dropoffs 
over 10'; low railings, 
no fence 


Fenced pathway 


Fenced pathway 


Reasons for Treatment 
Disabled 


for 


Followed accessibility 
standards when widen- 
ing faci 1 i ty; local 
request for widening 


Not appl I cable 


Local request for 
construction of 
facility; followed 
draft state standards 


NOTE: To convert to 


metric 


Feet x 0.3048 - Metres 





86 



Pedestrian crossing 
of Greeway on- ramp 
Mi 1 Ibrae Avenue 




Approach to 
Ahwanee 
pedestrian 
overcrossing 
Note Z gate 
on slope 



Figure 3, 



HANDICAPPED USER PANEL EVALUATION SITES 
Cal i forn ia 



U7 



Table 7. Florida Overcrossings - 
Evaluated by Handicapped User Panel 



Site Specifics 


Overcrossing Locations 






Sample Road 


Palmetto 


Route 27 


Seminole 




Pompano Beach 


Expressway 
Miami 


Hialeah 


Park 
Plantation 


Surrounding Land Uses 










Multi-Unit Residential 


No 


No 


No 


No 


Single-Unit Residential 


Yes 


Yes 


Yes 


Yes 


Comme re i a I /Pub 1 i c 


Yes 


Yes 


Yes 


Yes 


Industrial 


No 


No 


No 


No 


Open Space 


No 


No 


Yes 


Yes 


Adjacent Major Activity 


School 


School 


Park, Stores 


High School 


Centers 








Auditorium, 
Ball Fields 


Obstacle Crossed 


Freeway 


Freeway 


Arterial , Water 


Water 


Date of Faci 1 i ty 










Construction 


1972 


1976 


Unknown 


1977 


End Conditions 


Narrow pedes- 


2- lane residen- 


Two intersecting 


Parking lots 




trian pathways; 


tial streets 


k- lane signal- 






pathway on one 


with sidewalks 


ized streets 






side leads to 


on one s i de 


with sidewalks, 






residential 




both sides 






street 








Approach Conditions 


2 spiral ramps, 


2 straight 


3 switchback 


2 short paved 




16 feet high 


ramps, each 297 


ramps 


ramps 




from ground 


feet long 






Structural Conditions 


222 feet long; 


188 feet long 


2 spans at right 


128 feet long 




8 feet of clear 


span; 8 feet of 


angles; 5'8" of 


span; 8 feet 




width between 


clear width 


clear width 


of clear width 




curbs on span 


between curbs 
on span 


wa 1 kway 


between chained 
1 ink fence on 
span 


Access ibi 1 i ty 










Pedestrians 


Yes 


Yes 


Yes 


Yes 


Blcycl ist 


Yes 


Yes 


Yes 


Yes 


Motor Vehicles 


No 


No 


No 


No 


NOTE: To convert to metric 


: Feet x 0.30A8 


* Metres 







b& 






Blind pedestrian crossing 
bridge over canal 
Plantation, Florida 




Passing on narrow bridge 
over Route 27 
Hialeah, Florida 



Long ramp serving pedestrian 
overcrossing of Palmento Exprway, 
Miami , Florida 



Figure 10. HANDICAPPED USER PANEL EVALUATION SITES 
Florida 



89 




Ascending steep inside 
edge of spi ral ramp 
Pompano Beach, Florida 



m 





Handicapped panel discussion 
and debriefing 



Figure 11 



Narrow variable width path 
leading ot overcrossing 
ld&? Pompano Beach, Florida 

' * : r 

HANDICAPPED USER PANEL EVALUATION SITES 
Flori da 



90, 



The major problems experienced by the handicapped panel included steep and 
variable grades on the spiral ramps and lack of handrails; other findings 
are listed in the following section. 

The pedestrian overcrossing of the Palmento Expressway north of 
36th Street in Miami has straight ramps approximately 300 feet (91 «^M) 
long providing access to the structure crossing the expressway. Although 
the ramp grade was 8.33 percent, there was no intermediate rest areas. 
The length of the single long ramp appeared to be a psychological as well 
as a physical barrier to handicapped panel members except the blind person, 
Lack of handrail was also considered a significant deficiency. 

The pedestrian overcrossing of Route 27 in Hialeah has three switch- 
back approach ramps on each side to gain the elevation necessary to cross 
the highway and canal. Ramps were about 80 feet (2^.*tM) long between 
landings. This design was perceived by wheelchair-bound panel members 
to be more accessible than the long continuous ramp at the Palmento 
Expressway structure. The psychological problem of a long ramp was also 
relieved with the switchback configuration. The 5 feet 8 inches (1.7M) 
clear width walkway caused some persons to slow or stop when passing 
other persons. While this was noted as being an inconvenience, more 
concern was directed toward end conditions where drop-offs adjacent to 
the sidewalk were considered a hazard; particularly to a blind person. 

The prestressed bridge in Plantation, Florida spanned a canal be- 
tween two parking lots adjacent to a school ball field and auditorium. 
This overcrossing had very short ramps since the structure had to only 
have minimum clearance over the canal. Crossing this structure was rela- 
tively easy for all handicapped panel members. 

6.5.3 Summary of Findings 

The following summary of findings relating to handicapped accessi- 
bility on over and undercrossings identified during the handicapped user 
field evaluations and reviews by project team members is presented 
under four categories: (1) signs, signals and markings, ^main- 
tenance, (3) design features and (k) general conclusions. 

Sign, Signals and Markings 

• Advanced warning signs for motorists at striped crosswalks were 
lacking where pedestrians must cross high speed roadways and 
ramps. 

• Directional and guide signing were often lacking. Where 
present, they were considered helpful in providing potential 
users with information regarding crossing location, destination 
points, length and special features or conditions. 



91 



• Signs reinforcing information to reassure users that they are 
on the proper route were lacking. These were viewed as 
particularly important if there are many first time users or 
infrequent users as could be expected in the vicinity of trans- 
portation terminals or recreation areas. 

Maintenance 

• Dirt or sand on the pavement can reduce traction and make traveling 
difficult for certain handicapped persons. 

• Glass can become imbedded in wheelchair tires and cut a person's 
hands as they turn the wheels. 

• Trash cans or other moveable objects placed randomly in a 
pathway create special problems for blind persons. 

• Vandalism of signs and fencing that result in objects protruding 
into the pathway space is a hazard to all users. 

• Fence patches are often left with jagged fasteners exposed to 
the touch. 

• Differential settlement of sidewalks at the structure interface 
should be patched to provide a smooth transition. 

Design Features 

Sidewalk Characteristics 

• Lack of curb cuts or inconsistent use of curb cuts prevents 
wheelchair-bound persons from travelling freely along certain 
corridors. 

• Excessive cross slopes adversely affects handicapped persons 
guiding wheelchairs or wheeled walkers by making it more 
difficult for them to travel without veering toward the low 
edge of the pavement. 

• Super elevated roadway ramps create a similar problem by 
requiring extra effort and more time to cross in the uphill 
di rection. 

• Level rest areas should also be placed at points of pedestrian 
crossings of roadway ramps so persons about to cross do not have 
to cope with sidewalk slope as well as roadway slope. 

• Level resting areas are needed at reasonable intervals along 
long or steep ramps. 



92 



• Narrow sidewalks (i.e. less than 6 feet or 1.8M for two-way 
travel) were viewed as a hazard by wheelchair users and the 
blind and as an impediment to travel by all disabled panelists. 

• Drop-off s close to sidewalks pose a hazard and should be fenced 
or transitioned to minimize the problem. 

• Right angle sidewalks can be difficult for wheeled handicapped 
persons to negotiate, especially if they are narrow. Widening 
the pavement at the angle facilitates turning movements. 

• Steep ramp slopes were a major problem for all panel members 
except the blind. The steepness was found in several forms. 
It could be uniform along the entire ramp or at localized 
points. Also, it could be variable such as occurs between the 
outside and inside edge of a spiral ramp. 

• Unless the inside edge of a spiral ramp is specified to not 
exceed the maximum acceptable grade, grades along the inside 
edge will exceed acceptible standards because the grade on the 
inside edge is always greater than in the middle or on the 
outside edge of a spiral ramp. This is important because the 
inside edge provides the shortest travel distance and is thereby 
favored by most users. 

• Switchback ramp designs create intermediate landings or rest 
areas as well as lessen the psychological impact of long 
straight ramps. However, persons with coordination loss may 
have problems with the switchback configuration. 

• Smooth or slick pavement surfaces were viewed as a deficiency 
especially where ramps became steep. Rough pavement finish, 
built new or applied later, was considered a benefit. 

• Structural joints, unless relatively narrow or smooth, caused 
uncomfortable jolting as wheelchair users passed over them. 
Differential sidewalk settlement frequently occurs at the 
interface with the structure, thereby creating a bump. At a 
minimum this results in discomfort to wheelchair users or 
bicyclists and at worse can represent a safety hazard. 

• Sidewalk approaches should be at least as wide as sidewalks on 
the facility. If they are not, then a reasonable transition 
should be constructed. 

• A single curb cut on diagonal at a corner creates orientation 
problems for blind persons trying to select their walking 
direction across the street. 



93 



• Landings at the bottom of ramps adjacent to traffic should 
provide sufficient space for a number of users to pause before 
continuing their journey. 

Appurtenances 

• Graspable handrails are viewed by many handicapped persons as 
being an essential element of design on approach ramps or stairs 
Another area where handrails are important is where there are 
drop-offs close to the pathway which present a potential hazard 
to blind persons and wheelchair users. 

• Inadequate sight distance is considered a major deficiency, 
whether occurring on the facility or at a roadway crossing. 

e Indirect routes or pathway junctions on the structure can be 
confusing to the blind. 

• Fences were considered helpful. However, problems may occur 
where bracing or fencing intrudes into the pathway as a result 
of vandal ism. 

• Curbs constructed on both sides of exclusive pedestrian over- 
crossings were found to have four positive features, they: 

1) help to channelize drainage; 2) provide support to fence 
posts; 3) can be used as resting places for tired travelers; 
and 4) provide ideal boundaries for blind cane users. 

e Barrier posts should only be used if they serve to block access 
of motor vehicles to non-motorized facilities and should be 
ref lectorized to enhance nighttime visibility. They should be 
removed at locations where they are not effective. 

• Well traveled short cut routes serving the facility should be 
formalized if deemed safe. 

General Conclusions 

• The disabled are a heterogeneous group with varied mobility 
limitations and needs. Persons with the same medical condition 
are likely to vary in their physical stamina and perceived 
fears about making level changes. It is important to note that 
this project's evaluators are active disabled people who are 
likely to be less fearful of new experiences than are many of 
the disabled population. 

• A combination of treatments is needed to make a facility bar- 
rier free. Even then, a facility may not be used by some dis- 
abled groups who anticipate that the crossing trip will take 
too much effort. 



3h 



The method of using handicapped panelists to conduct on-site 
evaluations was successful in this study and can be a useful 
technique for local and state officials to use in planning new 
or retrofit construction. 



6.6 SUPPLEMENTAL FIELD INVESTIGATIONS 

In addition to the pilot study and the five sites selected for 
detailed evaluation, approximately 200 other structures were visited in 
17 states and in Washington, D.C. Of the 72 case studies documented 
during the study, k] were visited and inspected in the field. Over 1,000 
photographs were taken to document site and user characteristics during 
the study. 

Locations visited to examine one or more design and/or operational 
features or to generally add to the study team's background knowledge 
and data base were chosen based on personal knowledge, or at the sug- 
gestions of others. Visits were made whenever the opportunity presented 
itself. These sites tended to be located in the vicinity of the study 
team's offices and at sites at or adjacent to areas which were visited 
primarily for other purposes throughout the study. 

The supplemental field investigations have produced an important 
reservoir of information which has been used to broaden the insight 
gained from those sites receiving more detailed evaluations. The 
additional information has been included in the findings and results 
presented throughout this report and particularly in the formulation 
of the design strategies described in Chapter 7. Figures 12 through 
]k contain a sample selection of photographs taken during the supplemental 
site visits, illustrating both deficiencies and examples of good practice. 

Photographic views presented In Figure 12 show a variety 
of different structural treatments. The exclusive bicycle and 
pedestrian undercrossing of a local roadway is in a planned unit 
development. An older railroad underpass shows where metal railing 
and splash boards protect pedestrians using narrow sidewalks. The 
bicycle and pedestrian overcrossing with lighting connects to a 
parking lot on a university campus. The overcrossing ramp gains 
access from a median between a freeway and a frontage road. A side- 
walk on one side of the roadway crosses a small bridge on the outskirts 
of a small town. Finally, a wooden bridge with wooden piling built 
through a marsh is designed so the deck can be jacked up to 
compensate for differential settlement. 

Several signs indicating various unique traffic control strate- 
gies are shown on Figure 13. Additional photos illustrate an under- 
pass from a canal levee underneath the approach to a highway bridge. 
This provides levee protection from high water. The other undercrossing 
is constructed of corregated metal pipe and connects a residential 
area to a major street on the other side of an elevated railroad 

95 




Figure 12. SELECTED SITE VIEWS 



96 




Figure 13. SELECTED SITE VIEWS 

97 



track. The final photo displays the underside of a dual highway 
bridge where a centrally located pedestrian and bikeway is incorporated 
in the structure. Access returns to each side of the roadway from 
a pathway under the bridge abutments. 

The effectiveness of grating to reduce the effects of snow on 
a ramp to overcrossing is one feature shown Figure 14. Another 
view of the same ramp displays a unique treatment for driveway access. 
The keyhole like undercrossing is an old corregated pipe tunnel with 
ramp access to one approach and stair access on the other. Curvilinear 
wing walls serving a railroad overpass are set back from the roadway 
to allow a future shoulder or bikeway to be added. The continuous 
shoulder along a divided highway provides ample space for occasional 
non-motorized usage in this rural location. The protruding platforms 
over each pier along this major highway bridge connect to a wide 
one-sided bicycle and pedestrian path and serve as observation or 
resting areas for recreational ly oriented bicyclists and pedestrians. 



9u 




Figure 14. SELECTED SITE VIEWS 



99 



CHAPTER 7 

DESIGN APPROACHES AND STRATEGIES 

7.1 INTRODUCTION 

This chapter presents a distillation of findings, conclusions and 
recommendations concerning facilities for non-motorized travelers on 
over- and undercrossings. Major sections describe a presentation of 
general design considerations, standards and features; a discussion of 
design strategies and effective treatments which includes generic, 
prototypical designs for five different types of new projects and 
three kinds of retrofit projects, as well as discussions of non- 
structural solutions and some potentially applicable innovative tech- 
niques; an approach to improving the awareness and understanding of 
both system designers and users through education, and a discussion 
of handicapped user considerations. The chapter concludes with a 
summary, drawn from current practice, of the examples of good and 
deficient design features. Accompanying the latter are suggested ways 
of overcoming, or at least ameliorating, unsatisfactory character- 
istics or conditions. 

7.2 DESIGN CONSIDERATIONS, STANDARDS AND FEATURES 

There are a number of common design elements which apply to all 
non-motorized facilities on over- and undercrossings. These are dis- 
cussed below prior to presentation of prototypical design strategies 
for new and retrofit facilities in the following section (7.3). 

7.2.1 Over- and Undercrossings as Systems 

Over- and undercrossings are part of an existing transportation 
system. Whether they are jointly shared by motor vehicles and bicyc- 
lists and pedestrians, or intended solely for use of the non-motorized 
traveler, they interface with existing highways, bikeways and pedes- 
trian ways. To function smoothly as part of the transportation net- 
work, their design must be continuous with the existing facilities, as 
well as compatible with future plans. By definition, grade separa- 
tions have three components, namely end conditions, approaches and the 
structure (see Figure 2). To be properly designed, each component 
should be considered as part of a system rather than being an inde- 
pendent feature. 

7.2.2 Design Elements 

The design of non-motorized facilities can be divided into two 
areas: 

100 



• Geometries 

• Details, Special Features and Construction Materials 

These subdivisions apply equally to grade separations shared with 
motor vehicles, those exclusively serving non-motorized travelers, and 
to new and retrofit situations. Application of specific design stand- 
ards and solutions of special features are largely a function of the 
types of users anticipated and local design policies and circumstances. 

Geometries . Geometries encompasses the determination and rela- 
tionship of the physical dimensions of facilities. For the non- 
motorized traveler, the following items are of importance, defined as 
follows, and values are listed in Table 8. 

• Clear width — unobstructed travel width on the structure and 
approaches. 

• Grades -- maximum slope and average slope. 

• Cross slope -- slope across the facility surface perpendicular 
to the normal direction of travel. 

• Design speed (bicycle) -- the speed at which a bicyclist can 
travel in safety and comfort. 

• Design curvature (bicycle) — radius of curvature consistent 
with the design speed of the bicyclists. 

• Sight distance -- distance required to see an object cr other 
non-motorized traveler on the facility and stop or avoid 

col 1 is ion. 

• Overhead and lateral clearance -- space required above and on 
each side of travel way for safety and comfort of moving, non- 
motorized travelers. 

Design decisions made regarding the geometric elements determine 
the basic quality of travel on the facility. 

Standard geometric elements are outlined in several publications. 
Usually the standards set forth are pertinent to one user group, that 
is, either for bicyclists or pedestrians or the handicapped. Table 8 
shows relevant design guidelines and notes of explanation in a compara- 
tive manner for all three users. These have been derived from a 
number of sources, as noted on the table. Maximum or minimum criteria 
and desirable criteria are shown where possible. 

While standards are useful guides for good design practice, indis- 
criminate adherence should be avoided. Their use must be tempered by 
engineering judgment based on prudent assessment of individual and 

101 



Table 8. Design Guidelines for Geometric Elements 



Geometric 


Bicycle 


(22,51,62) 


Pedestrian (15,52) 


Handicapped (61,63) 


Max. 




Max. 


Max. 


Element 


or Min. 


Desi rable 


or Min. Desi rable 


or Min. Desi rable 


CLEAR WIDTH 










One Lane 


3.5 Ft. 


4.0 Ft. 


3.0 Ft. 4.0 Ft. 


3.0 Ft. 4.0 Ft. 




(Min) 


(or more) 


(Min) for more) 


Min (or more) 


Two Lanes 


7.0 Ft. 


8.0 Ft. 


6.0 Ft. 7.0 Ft. 


4.0 Ft. 5.5 Ft. 




(Min) 


(or more) 


(Min) (or more) 


Min (or more) 

(Pass Two 
Wheelchairs) 


More than 


Where vol 


umes of any or 


all of the user groups are 




Two Lanes 


heavy, ca 


lculate widths 


required using level of 






service concepts. 






CLEARANCE 










Vertical 


3.33 Ft. 


9.5 Ft. 


7.0 Ft. 8.0 Ft. 


(Same as pedestrian) 


Unobstructed 


Min 




(Min) 




Height 










Lateral 


1.0 Ft. 


2.0 Ft. 


1.0 Ft. 1.5 Ft. 


(Assume same as pedestrian) 


Clearance to 


Min 




(Min) (or more) 




obstructions 










GRADES 


10.0% 


5.0% 


15.0% 5.0% 


8.33% 5.0% 




(For dist. 


(For Dist. 


(Max) 


Max (or less) 




of 50 Ft. 


of 300 ft. 




(Length of 




or less) 


or less) 




single run 




Max 






is 30 feet 
run) 


CROSS SLOPE 


2.0% 


Calculated 


6.0% 5.0% 


2.0% 1.0% 




(Min on 


from super- 


(Max) (or less) 


(Max) (or less) 




curves) 


elevation 
formulas 






DESIGN SPEED 


10 MPH 


15 MPH 


Not Appl icable 


Not Appl icable 


(Bicycles) 


(Min) 


(20 MPH 
on long 
down 
grades) 






RADIUS OF 


15.0 Ft. 


Calculate 


Not Appl icable 


Not Appl icable 


CURVATURE 


(Min) 


from 






(Bicycles) 




appropriate 
formulas 
(See Table 

10) 






SIGHT DISTANCE 


Varies wi 


th grade 


Sight at curves 


Sight at curves and 




and speed 


. Ca leu- 


and turns must not 


turns must not be 




late frorr 


appropriate 


be obscured. Suf- 


obscured. Sufficient 




formulas 


(See Table 


ficient distance 


distance to avoid 




11) 




to avo id co 1 1 i s i on . 


co 1 1 i s i on . 



Source: Compiled by De Leuw, Cather 6 Company from references Nos.: 15,22,51,61 and 62 
NOTE: To convert feet to metres multiply feet by 0.3048. 



102 



collective needs of the non-motorized traveler, and features peculiar 
to a particular crossing situation. 

Details, Special Features and Construction Material . The special 
features and details listed are items that provide increased protection 
for users or enhance the travel characteristics of the over- or under- 
crossing. Their absence or lack of attention to their design may 
create an unacceptable situation for any of the three user groups. 
Judicious choice of construction materials can also result in an im- 
proved crossing experience. Particular consideration should be given 
to design or inclusion of the features listed below. 

• Motor Vehicle Barriers : Barriers should be erected to protect the 
non-motorized traveler on both the approaches and structure where 
vertical or horizontal separation from motor vehicles is other- 
wise unachievable, and where motor vehicle traffic is heavy or 
operates at high speed. Concrete barriers with a sloping face 

on the traffic side (New Jersey type) have proven very effective. 
Solid barriers also offer non-motorized users protection from 
being splashed by roadway wash. Railings may have to be affixed 
to the top of the barrier to reach the minimum vertical height 
desirable for protection of bicyclists and pedestrians. 

• Pedestrian Railings/Protective Barriers : What are commonly called 
"pedestrian railings" are really protective barriers to keep 
bicyclists, pedestrians or the handicapped from unintentionally 
leaving the facility. Pedestrian railings are commonly construct- 
ed of steel or aluminum pipe or tubing, wood, concrete, or some 
combination of these. Railings should have smooth surfaces and 

be free from protruding parts or discontinuities which can snag 
passers by. Where bicyclists are expected to use the facility, 
railings should have a minimum vertical height of *t.5 feet (1.^M). 
If only pedestrians and the handicapped have access to the facil- 
ity, a 3.5 foot (1.1M) height is sufficient. (22, 65) 

• Graspable Handrails : Handrails are placed on stairs and ramps to 
provide continuous support to aid pedestrians or the handicapped 
in ascending or descending. Handrails should be a part of all 
over- and undercross ings, preferably continuously across the 
approaches and the structure. If this is not feasible, at least 
those portions of the project with pronounced grades or slopes 
should have them. In addition to providing support for the handi- 
capped and elderly, handrails serve for emergency grasping by 
pedestrians to maintain their balance, and act as a rub rail for 
bicyclists, separating them from metal barricades or fencing. 

Handrails should be graspable, with a shape that allows natural 
opposing grip. Their height should be 33~36 inches (0.8-0.9M) 
above the surface vertically below, and if mounted next to or on 
a wall or other barricade, there should be a space between the 
wall and the handrail of approximately 1-1/2 inches (38mm). (61) 

103 



Curb Cuts and Ramps : Curb cuts and ramps are required features 
wherever curb barriers exist. They are essential for access by 
many types of handicapped persons, and are useful for both bicyc- 
lists and pedestrians. The minimum width of a curb ramp/cut should 
be 3 feet (0.9M) for one directional flow, k feet (1.2M) for two 
directional flows, and 5.5 feet ( 1 . 7M) to enable two wheelchair 
users to pass. The ramp slope should be a maximum of 1:12 (8.33 
percent). Whenever possible, lesser slopes should be employed. 
(52, 61, 63) 

Landings and Platforms : Level landings or platforms should be 
provided at the top and bottom of ramp runs, and intermediate 
landings should be provided on long ramps. Where the ramp grade 
exceeds 1:16 (6.25 percent), level landings should occur approxi- 
mately kO feet apart. Provision of rest areas may satisy the 
handicapped user equally as well and, therefore, intermediate 
level landings may not be necessary. The landing should have a 
clear width at least equal to the width of the largest ramp run 
leading to it. The minimum landing depth should be 5 feet 
(1.5M). (61) 

Rest Areas : A very desirable feature is strategically placed 
rest areas. Rest areas may be located within the traveled por- 
tion or off to the side. A flat grade and a place to sit or to 
rest against are typical features included at rest areas. They 
are particularly beneficial on very long over- and undercross- 
ings, and they can function as viewing areas along approaches and 
the structure in scenic areas. Care should be taken that rest 
area appurtenances do not intrude upon the travel space. A num- 
ber of promising strategies are illustrated which could serve 
as rest areas without requiring a level landing. These appear 
to be applicable to retrofit as well as new construction. See 
Section 7.3.6, Figure 29. 

Surface Finishes, Materials and Construction Joints : Unsealed 
gravel, cobblestone and corrugated surfaces should be avoided. 
Smooth, jointless construction (such as that afforded by asphalt 
concrete) is preferred by all user groups. Smooth concrete sur- 
faces are also good. Concrete surfaces should be made non-slip 
by use of broom finishes or an abrasive grain floated into them 
when they are laid. Wood plank decking is acceptable if joints 
are a maximum of one-half inch (preferably less) and warped 
planks are regularly refinished or replaced. Checker plate and 
walkway grating on structures functions well, if the surfaces 
are adequately roughened for slip-resistance. Grating appears 
to have a special advantage where snow fall is a regular occur- 
rence, since it minimizes snow accumulation. 



0*4 



Expansion and construction joints should be the minimum allowable 
by structural and construction considerations. If the joint is 
greater than one-half inch (13mm) wide, a cover should be pro- 
vided. A flush joint is desirable. Joint filler should not ex- 
pand above or shrink below the surface excessively. 

• Gratings : Drainage or other gratings that must protrude into the 
travel way of the non-motorized facility should have smaller 
openings than those commonly used. Large openings are a hazard 
to bicyclists, as they may "catch" wheels. If the grating bars 
are parallel, turning the grating so the bars are perpendicular 
to the direction of non-motorized travel may be an acceptable 
al ternative. 

Handicapped persons in wheelchairs or using crutches and canes 
are even more affected by grating openings. To prevent the 
catching of wheelchair wheels or crutch and cane tips, gratings 
within the travel way for these users have been suggested to have 
openings no greater than 3A inch by 3A inch (19 mm by 19 mm). 
In retrofit situations where gratings have been installed with 
larger openings, straps or bars welded to the gratings have been 
used to reduce the maximum opening. 

Placing drainage gratings so the bars are perpendicular to the 
direction of non-motorized travel, or reducing the openings will 
have adverse affects on their hydraulic characteristics. Welding 
straps or bars to drainage gratings has in some instances proven 
unsatisfactory, as motor vehicle traffic has dislodged the welds. 
Analysis of drainage requirements and careful detailing of bar 
or strap position, type and welding procedures should precede 
grating installation. (6k) 

7.2.3 Designing for Multiple Users 

Almost all facilities on over- and undercrossings for non-motoriz- 
ed travelers will be utilized by some bicyclists, pedestrians and 
handicapped persons. This is true for both new construction and 
retrofit situations. Planning, conceptual design, and construction 
activities for such projects, therefore, should generally be pre- 
dicted on concurrently meeting the combined requirements of bicyc- 
lists, pedestrians and the handicapped, not merely one user group. 

Design and the Application of Standards : Accommodating bicyc- 
list s7~ pTd!TsTrTa7rsT~a1n~crTh^^ may not be as 
formidable or as costly as might initially be supposed. Close ex- 
amination of desirable design standards and treatments for each user 
group reveals a great deal of overlap. Further, specific features 
that appear to be related to enhancing the travel of only one user 
type often improve it for the others as well. An example would be 
curb cuts and ramps installed for the handicappped, being beneficial 
to bicyclists and some pedestrians. 



105 



Unintentional exclusion of some users has occurred in certain 
situations because maximum and minimum standards were incorrectly 
utilized. This can occur because of the tendancy to use maximum and 
minimum standards to produce the least-cost project without the design- 
er taking the time to assess the actual needs of the non-motorized 
traveler who is expected to use the facility. This awareness of needs 
is particularly important because recent research has identified 
features and criteria which are not accounted for in historic design 
standards which themselves may be five or ten years or more old. 

Based on the above and observations made during the course of 
this study, the following conclusions can be drawn: 

1. The design standard for a geometric element acceptable to all 
user groups should be used; i.e., the lowest common denomina- 
tor, or "most desirable" design standard, should be selected. 

2. Details, special features, and construction techniques must 
be analyzed for potential effects on travel conditions for 
each of the three user groups. 

Selection of the "most desirable" design features appears to 
either enhance travel for the remaining users, or at least have a 
neutral effect. This fact is demonstrated in Table 9, where accepted 
"desirable" design guidel ines f rom Table 8 are summarized. When user 
groups associated with the "desirable" guidelines for these geometric 
elements are reviewed, it is found that the bicycle, not the pedes- 
trian or the handicapped, is the group determining the design. One 
conflict in designing for bicyclists, pedestrians and the handicapped 
as a group is that superelevations on curves considered desirable for 
bicyclists would often exceed the two percent cross-slope considered 
as a maximum for handicapped use. Unless it is possible to increase 
radii of curvature on approaches or structure, lower design speeds 
for bicycles will result. 

Another important consideration is that for long ramps or those 
with grades over 6.25 percent, intermediate landings or rest areas are 
needed for the handicapped. (6l) 

l.l.k Designing for the Handicapped 

Good design is based upon sound principles of engineering and 
planning, and is responsive to adopted policies determined by politic- 
al process. Policies can directly affect the design of over- and 
undercrossings by requiring adherence to certain standards, or by 
specifying inclusion of special features. The federal policy man- 
dating that over- and undercrossings be accessible to the handicapped 
overlies other design considerations and, thus, requires use of cer- 
tain standards and inclusion of special features as listed below. 
(52, 61, 63) 

106 



Table 9. Most Desirable Design Guideline 



Geometric 
Element 


Most Desirable Design Guideline 


Cri 


tical 


User Group 


Bike 


Ped 


Handicapped 


CLEAR WIDTH 










One Lane 
Two Lanes 


4 feet 1 lane min. (1.2M) 
8 feet 1 lane min. (2.4M) 


X 


X 


X 


More Than 
Two Lanes 

CLEARANCE 


Where volumes of any or all of 
the user groups are heavy, 
calculate widths required using 
level of service concepts. 


X 






Vertical 

Unobstructed 

Height 


9.5 feet (2.9M) 


X 






Lateral 
Clearance to 
obstructions 


2.0 feet (0.6M) 


X 






GRADES 


5 percent maximum 


X 


X 


X 


CROSS SLOPE 


1 percent or less 






X 


DESIGN SPEED 
(Bicycles) 


15-20 MPH (24-32KM) 


X 






RADIUS OF 
CURVATURE 
(Bicycles) 


See Table 10 


X 






SIGHT DISTANCE 


See Table 1 1 


X 







Source: Derived from Table 8. 



• Stairs: Stairways are unacceptable as the sole means of 
access to the structure. However, stairs may be used if 
these are in addition to ramped approaches, elevators or 
other conveyances. 

• Ramps: Ramped approaches by themselves are acceptable. 



107 



Table 10. Radius of Curvature - Bicycles (51) 



Design speed, 


Design radius, 


mph 


feet 


10 


15 


15 


35 


20 


70 


25 


90 


30 


125 



Table 11. Stopping Sight Distances - Bicycles (51) 



Design Speed 


Stopping 


Sight 


Distances 


for Downh 


11 


Gradients of: 


0% 




5% 


10% 




15% 


mph 


feet 




feet 


feet 




feet 


10 


50 




50 


60 




70 


15 


85 




90 


100 




130 


20 


130 




iko 


160 




200 


25 


175 




200 


230 




300 


30 


230 




260 


310 




400 



• Grades : The maximum allowable slope or grade on a ramp should 
be 8:33 percent, with lesser grade preferable. (63) 

• Cross-Slope : A cross-slope of two percent or less is prefer- 
red. 

• Graspable Handrails : Handrails capable of being securely 
grasped should be provided on portions of the project with 
grades or slopes. Preferably the handrail should extend con- 
tinuously along the approaches and across the structure. 

• Curb Cuts and Ramps : Curb cuts and ramps are required at 
appropriate locations. 

• Landings and Platforms : Level platforms must be provided at 
the top and bottom of ramp runs, and intermediate landings or 
rest areas should be provided on long ramps. 



108 



7.3 DESIGN STRATEGIES AND TREATMENTS 

7.3.1 Introduction 

For each proposed crossing of a barrier there are usually a very 
large number of possible solutions. Ensuring that as many potential 
alternatives as possible have been given consideration, and choosing 
the one that is most applicable, is di ff icul t for the designer. An 
effective method often used in practice is to examine a number of 
existing designs and solutions applied elsewhere for suggestions as 
how to best approach the situation being analyzed. 

Recommended design treatments have been developed as part of this 
research study to serve as a catalogue of potential strategies, and as 
a means of illustrating key design points. The design solutions have 
been grouped according to the major headings derived as part of the 
crossing classification and other aspects of the study described in 
Chapter 5. Design requirements have followed from the Field Evalua- 
tions discussed in Chapter 6. The following portions of this section 
have been organized as follows: 

• New projects - generic design strategies 

• Retrofit projects - generic design strategies 

• End conditions 

• Non-structural solutions to crossing problems 

• Unusual treatments, innovative designs, and new technologies 

Generic design strategies are defined for the purpose of this 
study as typical solutions to frequently encountered crossing problems. 
They are approaches to both new and retrofit situations that have been 
derived from a number of case studies and are generally applicable to 
a majority of crossing conditions. 

Eight generic or prototypical types of new facilities were selec- 
ted based on a review of the 72 case studies analyzed in the course 
of this study and using the classification described earlier in Section 
5-3-1 . These are as follows: 

• Overcrossing Shared with Motor Vehicles (k lanes or more, heavy 
traffic) 

• Overcrossing Shared with Motor Vehicles (2 - k lanes, light/ 
medium traffic) 

• Underpass Shared with Motor Vehicles (k lanes or more) 



09 



• Underpass Shared with Motor Vehicles (2 lanes) 

• Tunnel Shared with Motor Vehicles (light traffic) 

• Bicycle and Pedestrian Bridge (over 100 feet long - 30. 5M) 

• Bicycle and Pedestrian Bridge (less than 100 feet long - 30. 5M) 

• Minor and Major Bicycle and Pedestrian Undercrossings 
(Underpass and Tunnel) 

Similarly, six generic prototypical types of retrofit facilities 
were selected: 

• Cantilever Addition of Bicycle and Pedestrian Facilities to an 
Overcrossing. 

• Addition of Bicycle and Pedestrian Facilities to an Undercrossing 
by use of Traffic Barriers. 

• Upgrading of Bicycle and Pedestrian Facilities on an Overcross- 
ing by Removing Existing Railings and Adding Traffic Barriers 
and Canti levers. 

• Expansion or Upgrading of Existing Bicycle and Pedestrian 
Faci 1 i ties. 

• Adding of Non-Motorized Travel Facilities While Widening an 
Existing Motor Vehicle Overcrossing. 

• Conversion of an Existing Over or Undercrossing to Exclusive 
Use for Bicyclists and Pedestrians. 

The end conditions that can be combined with a particular approach 
and structure situation are numerous. In order to simplify presenta- 
tion of the prototypical solution, potential end conditions have been 
grouped into a separate section of this report for ease of graphical 
presentation and discussion. 

Crossing problems can often be alleviated or even eliminated by 
non-structural solutions such as traffic control strategies; alterna- 
tive routes; alternative travel modes; new technologies, and land use 
planning. Illustrative examples for each of these strategy areas are 
described later in this chapter. 

The generic design strategies and prototypical alternatives have 
applicability to the majority of crossing situations. In some limited 
instances, unusual designs and techniques may prove to be the most 
effective. A number of these are presented below to encourage considera- 
tion of atypical solutions to non-motorized travel problems by providing 



no 



designers with some insight into effective innovative treatments which 
have been utilized elsewhere. 

7.3.2 New Projects - Generic Design Strategies 

For illustrative purposes it was determined that five generic 
prototypical types of new non-motorized facilities were the most basic. 
These are as follows: 

1. Overcrossing Shared with Motor Vehicles (k or more lanes, 
medium to heavy traffic) 

2, Underpass Shared with Motor Vehicles (k or more lanes, medium 
to heavy traffic) 

3* Bicycle and Pedestrian Bridge (over 100 feet - 30. 5M long) 

**. Bicycle and Pedestrian Bridge (less than 100 feet - 30. 5M long) 

5. Bicycle and Pedestrian Undercrossing (underpass and tunnel) 

Each prototypical solution illustrated on the following pages in 
Figures 25 to 29 contains a problem statement and a detailed graphical 
illustration of one or more solutions to the crossing problem. Key 
design considerations are noted on the i 1 lustration and outlined in 
detail by crossing element: end conditions, approaches, and the struc- 
ture. Standard features common to the design of the prototypical over 
and undercrossings are presented in Table 12. Special features are 
noted, and the advantages and disadvantages of the solution are compared. 
Reference is made by number to those of the 72 Case Study Sites that 
most closely correspond to the prototypical solution, so that an actual 
design and cost data can be examined, if desired. A list of the 72 
Case Study Sites with their corresponding reference numbers is included 
in the appendix. 



Ill 



NEW PROJECT 1 



FOUR LANE OVERCROSSING SHARED WITH MOTOR VEHICLES 



PROBLEM STATEMENT 

To incorporate two-way bicycle, pedestrian and 
handicapped facilities in the design of a new 
overpass or bridge, whose main puruose is con- 
veyance of motor vehicles. The project has 
heavy motor vehicle traffic with four or more 
lanes, speeds of 35 mph or more. 

Selected for illustrative purposes as shown in 
Figure 15 are the following characteristics: 

• A four lane bridge spanning a river. 

• Bicycle and pedestrian facilities on one 
side only. 

• End conditions are continuation of a major 
highway for the motor vehicle portion, with 

an existing or proposed bicycle and pedestrian 
trail . 

• The structure is steel plate girders with a 
reinforced concrete deck. 

• The approaches are long and on earth fill. 
DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 

Ends 

• Stripe center lines on all approaches where 
pathways intersect. Continuous center line 
may be necessary for high usage. 

• Install guide signs at pathway intersections 
to provide directional information. 

• Install pedestrian railing k.5 ft. minimum 
along the river embankment adjacent to the 
pathway intersection to prevent turning bicy 
cllsts from going off the path into the river. 

• Make curve transitions between approaches and 
end conditions smooth and avoid sharp turns. 

• Make the transition between grades as smooth 
as possible and avoid abrupt transitions. 

• Refer to the discussion on End Conditions 
beginning on page 1 Z5« 

Approaches 

• Preferred approach path material is asphaltic 
concrete because of jointless construction. 

• Install pedestrian rail a minimum of k.S ft. 
high along outside edge of path If shoulder 
area is narrow and slope is steep. 

• Place beam guardrail or traffic barrier be- 
tween path and roadway if separation is less 
than 5 feet. 



Structure 

• Width of the pedestrian and bikeway facilities 
varies from 8 ft. up to 16 ft., depending on 
anticipated volume of two-way bicycle and ped- 
estrian traffic. 

• Traffic barrier (half "Jersey" type) between 
roadway and blke/ped, with mesh fencing or 
tubular railing for total height of k.5 ft. 

• Outside railing Is 8 ft. high curved or vertical 
chain link or mesh if over a roadway to prevent 
trash from being thrown. If over water, a k.$ ft. 
(min.) height pedestrian railing should be 
provided. 

• Refer to Table 12 for standard features, such 
as pathway width, cross slope, cleatances and 
handrail placement, (see page 124) 

SPECIAL FEATURES AND CONDITIONS 

• Provide level grade breaks or rest areas on long 
grades and long structures. 

• The area between the traffic barrier and outside 
curb may act as a "trap" for both debris and 
water, unless carefully planned and constructed. 

• Lighting fixtures should be located outside of 
the clear width, such as behind the fencing or 
recessed In the fencing. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Lower cost due to combining bike and pedestrian 
facilities with construction of motor vehicle project. 

• Facility on one side is less costly than a facility 
on both sides of structure. 

• One-sided facility provides continuity with 
single trail on approaches. 

• Full separation of non-motorized traffic from 
motor vehicle traffic. 

Disadvantages 

• Aesthetic and psychological discomfort from 
sharing facility with heavy motor vehicle 
traffic; noise, air pollution. 

• Interaction between bicyclists and pedestrians 
may cause operation and safety problems. 

• One side facility may complicate end conditions 
in returning to existing sidewalk and street 
patterns. 

• Non-motorized travel may be lengthened by shar- 
ing a structure located primarily to optimize 
motor vehicle travel. 



NOTE: To convert to metres multiply feet x 0.3048. 



CASE STUDY REFERENCE 

No. 35, kQ, 1»5, 63, 69 (See appendix) 



112 



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to 



to 
to 
o 

cc 
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a: 



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CC 

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a. 



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3 



113 



FOUR LANE UNDERPASS SHARED WITH MOTOR VEHICLES 



NEW PROJECT 2 



PROBLEM STATEMENT 

To incorporate bicycle, pedestrian and handicapped 
facilities on both sides of the roadway as part of 
the design of a new motor vehicle underpass. The 
underpass is a major project, with four or more 
lanes of heavy motor vehicle traffic, and speeds 
in excess of 35 mph. It crosses beneath a rail- 
road or highway. End conditions are a continua- 
tion of the roadway. 

Selected for illustrative purpos«s as shown in 
Figure 26 are two configurations, labeled as 
Alternative A and Alternative B, having the 
following characteristics: 

Alternative A - Depressed Roadway 

The overcrossing is sufficiently long to allow 
the bicycle and pedestrian ways to be located 
away from the roadway. The overcrossing spans 
a depressed roadway. 

a. Roadway is depressed so pedestrian and bike- 
way can be located on the cut slope with 
both vertical and horizontal separation used 
to minimize grades. 

b. Roadway is depressed so pedestrian and bike- 
way can be elevated along the wall to provide 
a safe vertical separation from the adjacent 
roadway, as well as to reduce grades for 
pathway users. 

Alternative B - At-Grade Roadway 

Retaining walls are required to reduce the bridge 
scan, thereby restricting the space available for 
bicycles and pedestrians. The overcrossing is 
elevated from the surrounding ground surface and 
spans an at-grade roadway. 



App_ roaches 

• A pedestrian railing k. 5' high should be supplied 
on the outside edge of the elevated bike and ped- 
estrian ways, and a traffic barrier with rail to 
a height of k.S' on the traffic side of the road- 
way level bike and pedestrian ways. 

• Refer to Table 12 for standard features such as 
pathway width, cross slope, clearances and hand- 
rail placement, (see page 124) 

Structure 

• Refer to Table 12 for standard features such as 
pathway width, cross slope, clearances and hand- 
rail placement, (see page \Zk) 

SPECIAL FEATURES AND CONDITIONS 

• The sidewalks and bikeway placed on the slope or 
elevated from the roadway reduce the change in 
elevation required to pass from ground level 
underneath the structure. This makes the cross- 
ing much easier in terms of effort for all non- 
motorized travelers. 

• If sufficient space cannot be found on each side, 
the wide median in the center should be explored 
as an option for a pedestrian and bikeway. 

• May require supplemental lighting, depending upon 
length of underpass and location of pathway. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Lower cost due to containing construction of 
motor vehicle project with bike and pedestrian 
faci 1 i t ies. 



a. Roadway is at-grade so pedestrian and bike- 
way needs only horizontal separation from 
the roadway. 

b. Roadway is at-grade, therefore adjacent side- 
walk requires positive physical separation 

to ensure safety. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 



• Full separation of motor vehicle traffic from 
non-motorized traffic. 

• Maintenance of the bicycle and pedestrian facil- 
ities is done as a part of the motor vehicle 
project maintenance. 

• Grades minimized to facilitate non-motor izea 
travel . 



ends 



Continue the bike and ped way and the pedes- 
trian sidewalk configuration until rejoining 
the existing pedestrian and bike system. 



Disadvantages 

• Aesthetic and psychological discomfort from 
sharing facility with heavy motor vehicle 
traffic; noise, air pollution. 



Continue the traffic barriers and pedestrian 
rails until there is no grade or normal ground 
level is reached beyond the underpass. 



CASE STUOY REFERENCE 
No. 71 (See appendix) 



• Refer to the discussion on End Conditions 
beginning on page 125- 

NOTE: To convert to metres multiply feet x . 30*»8 



114 



^\r 



Alternative 1B 



Normal 
ground 
level 




8' (mln) 

pedestrian and 
blkeway width 

Retaining 
wall 



Pedestrian railing 
4.5'(mln) with 
graspable handrail 



Alternative 1 - Section View 
Bicycle and Pedestrian Ways Separated from Depressed Roadway 




Alternative 2B 



4.5' (mln) 

k 



tf. 



New Jersey 
barrier with 
railing 



■ — — /IW^m 

8' (mln) 

pedestrian and 
blkeway width 

Retaining 
wall 



Alternative 2 - Section View 
Bicycle and Pedestrian Ways Adjacent to At-Grade Roadway 



Figure 16. NEW PROJECT 2 - FOUR LANE UNDERPASS 
SHARED WITH MOTOR VEHICLE 



115 



NEW PROJECT 3 



BICYCLE 



PEDESTRIAN BRIDGE OVER 100 FEET LONG 



PROBLEM STATEMENT 

To incorporate a long span overcrossing or bridge 
to exclusively serve two-way bicycle, pedestrian 
and handicapped travel over water, a roadway or a 
railroad. This is a structure with a span of 
greater than 100 feet. 

Figure 17 shows cross-sections of four potential 
structural and configuration types for exclusive 
bicycle and pedestrian overcrossings. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 

Ends 

• Use centerl ine to delineate all approaches to 
the intersection between pathways. 

• Stripe crosswalk and centerl ine on adjacent 
street. 

a Install advance warning signs to indicate 

pedestrian crossing. Use school crossing signs 
and markings where applicable. 

• Install guide signs to provide directional 
information to potential overcrossing users. 

• Refer to the discussion on End Conditions 
beginning on page 125 • 

Approaches 

• Refer to Table 12 for standard features such 
as pathway width, cross slope, clearance and 
handrail placement, (see page 124) 

• Protect pedestrians and bicyclists from steep 
slopes at the edges of approaches with 4.5 
foot high fencing. 

Structure 

• Rest areas should be considered as part of 
the design. 

• Apply non-skid surfacing to the structure 
decking and ramped approaches. 

• Provide lighting well protected from vandalism. 

• Refer to Table 12 for standard features such 
as pathway width, cross slope, clearance and 
handrail placement, (see page 124) 



SPECIAL FEATURES AND CONDITIONS 

« Cost and aesthetic advantages may be realized 
by sharing the crossing with utilities. 

• View screening may be necessary to preserve 
residential privacy. 

• Shielding of certain lighting fixtures may be 
required to reduce impact on residences. 

• Spiral ramps could save space. 

• The area adjacent to the spiral ramp may be 
suitable for mini park. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Complete separation from motor vehicle traffic; 
safety; reduction in noise and air pollution. 

• More direct access to bicyclist and pedestrian 
destinations. 

Disadvantages 

• Possible operational difficulties in rejoining 
the existing street and pedestrians travel 

s ystem. 

• Higher cost than facility shared with motor 
vehicles. 

• Separate maintenance arrangements required. 

CASE STUDY REFERENCE 

Nos. 33, 34, 35, 38, 44, 47, 49, 56, 64, 65, 66 

(See appendix) 



SOTE: To convert to metres multiply feet x 0.3048. 



8'(mln) If 
over roadway 
otherwise 

V5'(mln) 



Concrete 
prestressed 
gl rder 



8'(mln) two-way 
b Ike/pedestrian 
path 

Graspable 
handral I 



~k 



Non-skid 
surface 




Pedestrian 
rail 




Aesthetic 
shape 



Potential 
utl I Ity space 



Prestressed Concrete Girder 



Up to 16' wide for 
heavy two-way bicycle 
pedestrian traffic 



8'(mln) If 
over roadway 
otherwise 
*.5M»ln) 




— Pedestrian 
ral I ing 



Graspable 
handral I 



Potential 
utl I Ity space 



Prestressed Concrete Double Tee 



Figure 17- 



NEW PROJECT 3 
OVERCROSSINGS 



BICYCLE AND PEDESTRIAN 



117 



8'imln) 
two-way bike/ 
pedestrian path 



Pedestrian 
ral I Ing 

Graspable 
hand ral I 

Reinforced 
concrete deck 




l».5'(mln) 



8'(mln) 



Potential 
utility space 



8' ("tin) two-way 

b Ike/pedestrian path 



Graspable 
handrail 



Metal or wooden 
planking and/or 
metal grating 



II I 



3Z2ZU 



l.L 



Full height 
fencing If 
over roadway 
otherwise 

*.5'(mln) 

Steel truss 
structure 

Non-skid 
surface 

Potential 
utility space 



Welded Steel Plate Girders 



Steel through Truss 



K 



03d 
3NIX 



Crosswalk 



XING 
PEO 



Spiral ramp 
to save space 




Maximum slope 
8.33% provide 
rest/grade 
break area, 
If over 6.25* 



Plan View 



< Directional t Guide Signs 
Striping 



Figure 17. NEW PROJECT 3 - BICYCLE AND PEDESTRIAN 
0VERCR0SSINGS (Continued) 



118 



NEW PROJECT 4 



BICYCLE AND PEDESTRIAN BRIDGE LESS THAN 100 FEET LONG 



PROBLEM STATEMENT - 

Incorporate a medium or short span overcrossing or 
bridge for two-way bicycle, pedestrian and handi- 
capped travel. The length of the structure is less 
than 100 feet. 

Figure 18 shows cross sections of five potential 
structural configurations for exclusive bicycle 
and pedestrian overcross ings of short length. 
The following characteristics and features are 
illustrated as common for all the structural types: 

• Eight foot minimum clear width for two-way bike 
and pedestrian traffic. 

• Pedestrian handrails a minimum of k.$ in height. 

• Graspable handrails on both sides. 

• Deck or approach cross slope of two percent 
maximum. 

• Application of non-skid surfacing materials. 
DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 
Ends 

• Refer to the discussion on End Conditions 
beginning on page 125. 

Approaches 

• Continue pedestrian railing or fencing for a 
short distance to channelize users onto bridge. 

• Area adjacent to the bridge may be suitable 
for off-path rest area or view point. Addi- 
tional fencing may be necessary alonq the top 
of the creek embankment If this area is used. 

• Refer to Table 12 for standard features, such 
as pathway width, cross slope, clearances and 
handrail placement, (see page 12*0 

Structure 

• Deck cross slope is not necessary with wood 
plank or metal grating, because water drains 
through. 

• Refer to Table 12 for standard features, such 
as pathway width, cross slope, clearances 
and handrail placement, (see page t2*») 

NOTE: To convert to metres multiply feet x 0.3048. 



SPECIAL FEATURES AND CONDITIONS 

• Handrails and beams constructed of wood may be 
subject to vandalism. 

• Utilities could also use the same crossing with 
cost and aesthetic benefits. 

• Prefabricated structures can shorten construc- 
tion times and reduce costs. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Complete separation from motor vehicle traffic; 
Improvement in safety; reduction in noise and 
air pollution discomfort. 

• Relatively low cost structure constructed with" 
out Interruption of motor vehicle traffic. 

Disadvantages 

• Possible operational difficulties In rejoining 
the existing street and pedestrian travel 
system. 

• Higher cost than a facility shared with motor 
vehicles. 

• Separate maintenance arrangements required. 



CASE STUDY REFERENCE 

Nos. 26, 27, 28, 29, 31, 32, 39, ^2, 5A, 60 

(See appendix) 



119 



8' clear 



8' d« 



*.5' 
(■■In) 



3_ 



LET 



Non-skld waterproof 
surface. H" Plywood 
exterior grade T & G 



Ttf 



33"-36' 



2$ max 



1 



X 



V'xV posts 

Graspable 
handral I 

6"x6" 
continuous curb 



Glu Lam beams 



□ D 



Pile cap or 
abutment 



Glu Lam Beams with Plywood Deck 



*.$'(mln) 




V'xl2" or 
V'x8" decking 



r 



33"- 36' 



0» 



t! 



No cross slope Water drains 
between deck planks 



Steel tube 
pedestrian 
rails 

Graspable 
handrail 

WF Steel 
beams 



Rectangular steel 
tubing cross bracing 



Wide Flange Steel Beams 
with Wood Plank Decking 



8' cl« 



8' clear 



*.5' 
(nln) 



Non-skid 
surface 
V'x8" 
2*? Douglas 
Fir 



33"- 36" 



rPedestrl 
rail 

4^ 



Graspable 
handral I 

Glu Lam beams 

— Steel rod cross 
bracing steel 
pipe struts 



Glu Lam Beams with Wood Plank Decking 



4.5' (mln) 



J 



33"-36' 



Wood 

plank 

deck 



Add pipe or tube 
\ — pedestrian rail 

Graspable 
handral I 

Pre-fabrlcated 
steel truss 
bridge 



Pre-Fabrlcated Steel Truss 
with Wood Plank Decking 



8' Chain link 
ral I Ing If over 
roadway. H.S' (mln) 
pedestrian rail 
If over water. 



8' clear 



Broom finish 
concrete. 



L r^M 



33"-36" 



t'~ 



Graspable 
handrail 



Prestressed 
concrete tee 



Prestressed Concrete Tee 



Figure 18. NEW PROJECT k - BICYCLE AND PEDESTRIAN OVERCROSSING 
LESS THAN 100 FEET LONG 



120 



Potential 
off path 
res 



Creek 



Bike/pedestrian 
path 



»»»«•■■ "Vr 
t area < \M\ 



Pedestrian 
ral I Ing 




'; Bike and pedestrian bridge 



oT77 rest 



Potential 
off path 
area 




Motor vehicle bridge 



Plan View 
Possible Layout of Short Span Bike and Pedestrian Bridge 



Figure 18. NEW PROJECT k - BICYCLE AND PEDESTRIAN OVERCROSSING 
LESS THAN 100 FEET LONG (Continued) 



21 



BICYCLE AND PEDESTRIAN UNDERCROSSING 



NEW PROJECT 5 



PROBLEM STATEMENT 



Structure 



To incorporate a two-way travel bicycle and pedes- 
trian underpass or tunnel beneath a railroad, 
roadway or other barrier. Structures are differ- 
entiated by length, with lengths greater than 100 
feet considered to be long structures. 

Figure 19 shows cross sections for an arch-type 
tunnel structure and a narrow underpass. The 
following characteristics and features are 

i 1 I us t rated: 

• Eight foot minimum clear width for two-way 
bicycle and pedestrian traffic. 

• Pedestrian handrails a minimum of 4.5 in 
height in areas where there is slope. 

• Graspable handrails on both sides. 

• Two percent maximum cross slope. 

• Lighting installed if the structure is long. 
Protect lighting well from vandalism. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 

Ends 

• Consider connecting pathways between the 
pedestrian and blkeway using the under- 
crossing and the roadway above. 

• If connecting pathways are installed, 
directional guide signing will be necessary 
at both ends. 

• Refer to the discussion on End Conditions 
beginning on page 125. 

Approaches 

• Centerl lne striping may be needed to 
emphasize travel relationships approaching 
undercrossing. 

• Handrail should extend a minimum of 10 feet 
from the undercrossing and may be extended 
further, depending upon the grade. 

• Refer to Table 12 for standard features such 
as pathway width, cross slope, clearances and 
handrail placement, (see page \lk) 



NOTE: To convert to metres multiply feet x 0.3048. 



• Satisfactory drainage facilities should be 
built with grates and inlets compatible with 
bicycle and pedestrian usage. 

• Provide vandal proof lighting in tunnels or 
long underpasses. 

• Refer to Table 12 for standard features such 
as pathway width, cross slope, clearances and 
handrail placement, (see page 124) 

SPECIAL FEATURES AND CONDITIONS 

• Care must be exercised in maintaining adequate 
sight distance for bicyclists when entering or 
leaving the underpass or tunnel. 

• Side slopes approaching or within the under- 
crossing should be designed so that earth, gravel 
or other surface treatments are not a source of 
pathway debris. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Complete separation from motor vehicles; improve- 
ment in operational safety; reduction in noise 
and air pollution discomfort.. 

• Gentler grades and less vertical height differ- 
ential possible in undercrossing compared to 
overcrossing. 

• Less visible and less obtrusive than an over- 
crossing. 

Disadvantages 

• May be higher construction cost than overcrossing 
In certain settings or a facility shared with 
motor vehicles. 

• Separate maintenance arrangements required. 

• May be perceived as being dark, remote and having 
unpleasant environment subject to vandalism or 
loitering. This is especially true if the 
approaching users cannot see entirely through the 
underpass. 

• Small arch-type tunnels may be perceived as being 
overly restrictive unless used for only short 
distances and built to exceed the minimum width 
requi rement. 

CASE STUDY REFERENCE 

48, 50, 52, 58, 59, 67, 70 (See appendix) 



22 



Corrugated tteel 
multi-plate arch 
or reinforced 
concrete 



Lighting protected 
from vandals 




Graspable handrail 



Desired clearance 
at rail 8' (mln) 



A.C. paving 

Arch Tunnel Structure - Cross Section 



Connecting path 
as required 



Overhead structure 
p res tressed beam 




8' (mln) 



8' (mln) 

33"-36" 

Z% max I 2*max 



T 

A.C. paving 




Retaining 
wall 



Underpass - Cross Section 




Motor 

vehicle 

traveled 

way 



Connecting path 
as required ' 




r 



Pedestrian rait with 
graspable handrail 



Tunnel-Type Structure - Plan View 



Figure 19- NEW PROJECT 5 - BICYCLE AND PEDESTRIAN UNDERCROSSING 



123 



Table 12. Design Guidelines for 
Prototypical Over- and Undercrossings 5 



End Conditions 

• Curb cuts and ramps are constructed to facilitate access. Minimum 
width should be 3 feet (0.8m) for one direction and 4 feet (1.2M) 
for two-way travel and 5.5 feet (1.7M) to enable two wheelchairs 
to pass. (61) 

• Striping, signing and signals are installed to mitigate operational 
di ff icul ties. 

• Barriers are placed on exclusive paths to prohibit use by unauthor- 
ized motor vehicles. 

• Sight distance at pathway and street intersections are free from 
obstacles. (See Table 11) 

Approaches 

• Minimum pathway width is 5 feet (1.5M) for a pedestrian way or one- 
way path, and 8 feet (2.4M) for a combined pedestrian and bikeway. 
(22, 65) 

• Maximum grade is 8.33 percent, with 5 percent the desirable max. 
(51, 52, 63) 

• Maximum pathway cross slope is 2 percent. (64) 

• Grades in excess of 6.25 percent have grade breaks, landings or 
rest areas spaced periodically with a minimum landing depth of 5 
feet (1.5M). (61) 

• Preferred pathway surface is asphalt ic concrete because of its 
jointless construction and all-weather serviceability. 

• Fencing or protective barriers placed to separate non-motorized 
users from adjacent steep slopes and high speed traffic. 

• Graspable handrails 33"-36" (0.8-0. 9M) above the pathway surface 
wherever fencing is used. (61) 

• Minimum lateral clearance to obstacles is 1 foot (0.3M), with 2 
feet (0.6M) desirable. (22, 65) 

Structure 

• Pathway width, grade, cross slope criteria identical to approaches. 

• Graspable handrails 33"-36" (0.8-0.9M) above the pathway surface 
constructed continuously across structure. (61) 

• Physical barrier placed between two-way pathway and adjacent 
traffic lane. 

• Minimum fence height is 4.5 feet (1.4M) with bicycle usage, (65) 

• Non-slip surfacing used on pathway surface. 

• Vertical clearance minimum is 8 feet (2.4M). 

• Drainage gratings placed outside of pathway. 

"These guidelines were assembled from various sources and do not 
necessarily coincide with the adopted standards for any one agency. 

124 



7.3.3 Retrofit Projects - Generic Design Strategies 

For illustrative purposes it was determined that three generic 
prototypical retrofit solutions were the most basic. These are as 
fol lows: 

1. Cantilever addition of Bicycle and Pedestrian Facilities to an 
overcrossing 

2. Expansion or upgrading of Existing Bicycle and Pedestrian 
Faci 1 i ties 

3. Conversion of an Existing Over or Undercrossing to Exclusive 
use of Bicyclists and Pedestrians 

Each prototypical retrofit solution contains a problem statement 
and a detailed graphical illustration of one or more solutions to the 
crossing problem. Key design considerations are noted on the illus- 
tration and outlined in detail by crossing element-end conditions, 
approaches, and the structure. Special features are noted, and the 
advantages of the solution are compared. The three generic prototypi- 
cal types of retrofit projects are depicted in Figures 20, 21 and 22. 

Design strategies for retrofit projects act in a complementary 
manner to the ones for new projects, since features shown in one 
strategy could be applicable in another situation. 

Again, reference is made by number to those of the 72 Case Study 
Sites that most nearly correspond to the prototypical solution, so that 
actual designs and cost data can be examined, if desired. A list of 
the 72 Case Study sites with their corresponding reference numbers is 
in the Appendix. 

7.3.*t End Conditions 

As stated earlier, grade crossings have been defined for the pur- 
poses of this study as having three components: end conditions, 
approaches and the structure (see Figure 2). End conditions are fur- 
ther defined as being: that portion of the traveled way which is 
adjacent to the physical limits (on both ends) of an over- or under- 
crossing and which affects the ability of non-motorized travelers to 
use the crossing. All too often, primary attention is given to the 
design of the structure and its approaches, while the design at the 
end condition is neglected in comparison. It is important to re- 
emphasize that the three grade crossing components must not only pro- 
vide smooth linkage between themselves, but should be viewed in the 
context of the service provided within the surrounding system of 
non-motorized facilities. 

The purpose of this section is to define the basic types of end 
conditions and to describe potential problems and treatments. End 

125 



RETROFIT PROJECT 1 



CANTILEVER ADDITION OF BICYCLE AND 
PEDESTRIAN FACILITIES TO AN OVERCROSSING 

PROBLEM STATEMENT 

To incorporate a protected two-way pedestrian 
facility on an existing motor vehicle bridge. 
Bicyclists would have to either walk their bikes 
across, if the facility is one-side only, or ride 
across the motor vehicle portion at the edge of 
the traveled way. There is insufficient room on 
the bridge deck for a non-motorized facility. 

Partial section views of five cantilever struc- 
tural configurations are shown in Figure 20. 
Possible methods of attachment on three rein- 
forced concrete bridges or overpasses and two 
steel bridges or overpasses are illustrated. A 
plan view with the following characteristics is 
also shown. 

• A two-lane bridge spanning a river. 

• A pedestrian sidewalk on one side only. 
Bicycles must be walked across. 

• End conditions are a continuation of the road- 
way for the motor vehicle portion, and a 
continuation of the sidewalk. 

• Beam and post guardrail exists on both 
approaches. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 

Ends 

• Continue beam guardrail, as necessary, to 
protect walkway users. 

• Refer to the discussion of End Conditions 
beginning on page 125. 

Approaches 

• Install a pedestrian railing a minimum of 
4.5 ft. high on the outside edge of the path 
if the slope is steep. 

• A beam guardrail or traffic barrier should 
be placed between the approach path or side- 
walk and the motor vehicles if the separation 
is less than five feet, or if traffic is 
heavy or operates at high speed. 

• The approach shoulder may have to be widened 
to support the path behind the guardrail. 

A retaining wall may be required for the 
extra f i 1 1 material . 

• Refer to Table 12 for standard features 

such as pathway width, cross slope, clearances 
and handrail placement. (see page 124) 



Structure 

• Even with structural limitations, every effort 
should be made to meet or exceed the k foot 
minimum clear sidewalk width. 

• Opposing two-way travel on one side must be 
infrequent for a narrow sidewalk to function 
properly. 

o The existing abutments may have to be extended 
or modified to support the walkway. 

• The walkway deck could be constructed of wood 
planking, aluminum planking, steel grating, 
steel checker plate, precast concrete, or 
reinforced concrete poured in place. Surfaces 
should have an application of skid-proofing 
materials if they are slippery when wet. 

• The 4.5 ft. pedestrian rail should be carried 
across the walkway on the outside edge. 

SPECIAL FEATURES AND CONDITIONS 

• If conflicting two-way patronage is expected to 
be heavy, then a wider walkway should be con- 
structed, or if that is infeasible, walkways 
should be constructed on both sides of the 
structure if compatible with approaches. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Non-motorized users are fully protected from 
motor vehicle traffic while originally there 
was insufficient space on the overcross ing. 

• Construction costs and disruptions are minimized. 
Pi sadvan tages 

• Bicyclists may choose to ride in the roadway 
rather than walk their bikes across the canti- 
levered faci 1 i ty. 

• One side facilities only may complicate the 
operational safety at the end conditions. 

• Structural limitations may create substandard 
width walkways. 

CASE STUDY REFERENCE 

Nos. 4, 5, 11. 12, 13, 14, 15, 17, 22, 23 
(See appendix) 



NOTE: 



To convert to metres multiply feet x 0.3048. 



126 



Aluminum tubing 
pedestrian rail 



It' (mln) 



T 



- Graspab 
handra 



it. 5' (mln) 



WF beam 

stringers 

Bracing from 
both sides 
of pier cap 



33"-36" 
3Z2 



Add pedestrian 

rail to mlmlmum 



• fail LU Nil III I IIIU 

, f height of «t.5' 

i' 



Existing 
structure 

JL!j — . Reinforced 
concrete 



L Angle of both 
sides of pier cap 




To bridge 
center I Ine 

► 



Reinforced Concrete bridge - Part ial Section View 



Pedestrian 
rat I Ing 



ll.S'tmln) 



WF beam 
stringers 



V(mln) 



Plate hanger 
bol ted to 
existing curb 
curb 




Existing 
structure 

f ....... ....... To bridge 

center I Ine 



WF beam 



Concrete anchor 
bolts through 
beam flange 
alternate sides 



Reinforced Concrete Bridge - Partial Section View 



l»'(mln) 



Wood Joist 




To bridge 
centerl Ine 



Wood stringer 

steel angle bracing 

Sidewalk bracket 



. Existing beam 
Top of Bridge pier 



NOTE: Sidewalk could be all 
steel <s with steel 
checker plate flooring 
or aluminum planking 



Reinforced Concrete Structure - Part ial Section View 



Figure 20. RETROFIT PROJECT 1 - CANTILEVER ADDITION OF BICYCLE AND 
PEDESTRIAN FACILITIES TO AN 0VERCR0SSING 

127 



Graspable 
handral I - 



T 



VSMmln) 



Steel 

grating -I- 
or checker 
plate 



Pedestrian rail 



33"-36" 



WF beam 



T 



ED 

b 



E 



P 



Existing 
structure 

I 



fflW I WMMM. i m. il 



!l> & 1 



To bridge 
center I Ine 



Add pedestrian 
ral I to minimum 
height of k.S' 

Existing 
steel girder 

Added steel 
beam guardral I 



To bridge -r~ 

center) Ine 



Existing 
steel beam 



Graspable 
handral I 

Pedestrian 
rail 




Steel Truss Structure 
Partial Section View 



Steel Girder Structure 
Partial Section View 



rrxzx 



g B n a— 




Water 



Pier 

n 





a a t3 a m a " " 



n d n_ 



Edge of 
pavement 



Existing I 
bridge ral I ' I 



Exist Ing 
bridge 



I 



Existing 
guard rail 



iHH 



Tk 



l Cantilever sidewalk 



XT 



TTdewalk 



U U L) 



1 I V V '1 I 



J 

Lagging or J 
retaining wal I 
to support 
widened fill 
for sidewalk 



Pedestrian 
rail 




Lengthen abutment 
and wingwal I and 
modify to accomodate 
s I dewa I k 



One Side Cantilever Sidewalk Solution - Plan View 



Figure 20. RETROFIT PROJECT 1 - CANTILEVER ADDITION OF BICYCLE AND 
PEDESTRIAN FACILITIES TO AN 0VERCR0SSING (Continued) 



28 



EXPANSION OR UPGRADING OF EXISTING 
BICYCLE AND PEDESTRIAN FACILITIES 



RETROFIT PROJECT 2 



PROBLEM STATEMENT 

To provide protected bicycle and pedestrian facili 
ties on both sides of an existing underpass. The 
underpass has five-foot sidewalks on each side of 
a four lane divided roadway. 

DESIGN SOLUTION 

An entirely new widened sidewalk constructed away 
from the roadway is one solution. A second solu- 
tion involves widening the existing sidewalk and 
installing a physical barrier between the side- 
walk and traffic. (See Figure 21) 

Alternative A 

Relocation to an up slope position is more favor- 
able for a sidewalk along a depressed roadway 
since it minimizes grades. The existing sidewalk 
can be removed or may be retained if it provides 
an essential safety feature for emergency use of 
motor vehicle occupants. 

Al ternat i ve 8 



Widening of an existing sidewalk adjacent to the 
curb is equally applicable to at-grade, as well 
as depressed roadway designs. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 

Ends 

• Continue the traffic barrier until there is no 
grade from the depressed roadway or normal 
ground level is reached beyond the structure. 

• Conform to existing pedestrian and bikeway 
facilities at each end. 

• Refer to the discussion on End Conditions 
beginning on page 125. 

Approaches 

• The minimum width for simultaneous 

bike and pedestrian traffic is eight feet. 

• Construct a pedestrian rail A. 5 ft. high on the 
outside of the (Alternative I) bike and ped 
path that has been moved up the slope. 

• Construct traffic barrier with pedestrian 
railing on top to bring its height up to k. 5 
feet (Alernati ve II). 

• Refer to Table 12 for standard features such as 
pathway width, cross slope, clearances and hand- 
rail placement, (see page 12*) 



Structure 

• Construct low retaining walls, if necessary, for 
the walkway widening. 

• Refer to Table 12 for standard features such as 
pathway width, cross slope, clearances and handrail 
placement, (see page 125) 

SPECIAL FEATURES AND CONDITIONS 

• The area between the retaining wall and the 
traffic barrier can act as a "trap" for both debris 
and water, unless carefully planned and constructed. 

• 8ike lanes or shoulder stripes should be considered 
as a non-structural alternative or supplement where 
roadway space is available. 

• l_f sufficient space cannot be found on each side, 
the wide median In the center may offer an option 
for a pedestrian and bikeway. 

• May require supplemental lighting, depending upon 
length of underpass and location of pathway. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Two-sided facility crossing is coincident with the 
existing street and sidewalk patterns. 

• Bicyclists and pedestrians are fully protected 
from motor vehicle traffic. 

• Moving the path up the slope lessens its grade 
where the roadway is depressed. 

• Retrofitting existing facilities is less costly 
than constructing a 1 ternat ive routes or separating 
bicycle and pedestrian facilities. 

Pi sadvantages 

• Some bicyclists may choose not to use the bike 
path, preferring to ride at the edge of the 
traveled way. 

• If motor vehicle traffic is heavy, bicyclists 
and pedestrians may be bothered by noise and 
ai r pol lut ion. 

• Returning bicyclists and pedestrians to the 
existing street system may be complicated at the 
ends if a central median is utilized. 

CASE STUDY REFERENCE 
No. 71 (see appendix) 



NOTE: 



To convert to metres multiply feet x O^O^S. 



29 



r 




A 








Existing 
^-\5' sidewalk 




Existing 

5 ' si dewa 1 k ^^---' 









Existing Underpass - Section View 



Alternative 1 



8'(mln) 
clearance 

Retaining wal I 
If necessary 



6' (mln) pedestrian 
and btkeway width. 
Remove existing 
sidewalk optional 



\r. 




*.5'(mln) 

| pedestrian 

1 rails 



(mln) 



Graspable 
handral I 



Alternative 2 



*.5'(m!n) 

pedestrian 

rails 



~± 




Traffic 
barrier 



Retaining 

II If 
necessary 



8'(mln) 

pedestrian 

and blkeway 

width. 

Widen existing 

s I dewa I k 



L Graspable 
handrail 



Retrofitted Underpass - Section View 



Figure 21. RETROFIT PROJECT 2 - 
BICYCLE AND PEDESTRI 



EXPANSION OR UPGRADING OF EXISTING 
AN FACILITIES 



130 



CONVERT AN EXISTING OVER OR UNDERCROSSING 

TO EXCLUSIVE USE OF BICYCLISTS AND PEDESTRIANS 



KETRUFIT PROJECT. 3 



PROBLEM STATEMENT 

To convert an existing structure (railroad trestle, 
highway bridge, culvert) to exclusive use by 
bicyclists and pedestrians. Culverts are often 
used informally by pedestrians as undercrossings. 

DESIGN SOLUTION 

Potential conversion situations are depicted in 
Figure 22. An abandoned railroad trestle and high- 
way bridge are shown converted to exclusive bicycle 
and pedestrian use. A box culvert has been converted 
to facilitate bicycle and pedestrian use during low 
water conditions. 

DESIGN CONSIDERATIONS FOR CROSSING ELEMENTS 



Ends 



• Operational and safety problems may occur where 
the ends of converted structures merge into the 
existing street or pedestrian and bikeway system. 
Signing, striping and signals may help to mitigate 
these potential problem areas. 

• Curb cuts and ramps appropriately placed are an 
aid to handicapped and bicyclists in rejoining 
existing streets. 

Approaches 

Box Culvert 

• Make transition into culvert structure smooth 
and avoid short sections of steep grades. 

• Avoid curves or obstructions in approaches 
that could reduce sight distance. 

Highway Bridge 

• Protect pedestrians and bicyclists from steep 
slopes at edges of approaches with pedestrian 
rail or reuti 1 ization of metal guardrail. 

• Install posts or bollards to prevent motor 
vehicle travel over the bridge structure. 

• Repair and smooth asphalt concrete surfaces 
and joints. 

Rai 1 road Trestle 

• Remove and salvage existing railroad ties 
and resurface approach paths 

• Provide railings at the edges of steep fills 
adjacent to the structure. 

Structures 

Box Culvert 

• Elevate path sufficiently to be above low water 
flows — sidewalk or raised floor. 

• The minimum vertical clearance allowable is 
8 feet. 



Highway Bridge 

• Repair and patch the existing bridge surfaces. 

• Construct pedestrian rails k.S ft. in height 
at the outside edges. 

• Modify existing drainage inlets and grates as 

needed. 

Rai 1 road Trestle 

• Construct new decking over the existing bridge 
ties. 

• Construct pedestrian railings k. 5 ft. in 
height at the outside edges. 

SPECIAL FEATURES AND CONDITIONS 

• Vandal proof lighting should be considered for 
all of the structures, and particularly the 
converted culvert. 

• Consider railing along culvert sidewalk which 
can be removed during flooding seasons. 

• Protect pathway approaches to a culvert from 
stream erosion. 

DESIGN STRATEGY ADVANTAGES AND DISADVANTAGES 

Advantages 

• Lower cost because of use of existing structure. 

• Complete separation from motor vehicle traffic. 

• Use bridge or trestle which would otherwise need 
to be removed or be subject to unsightly 
deterioration. 

• Width of structure is more than adequate. 

• May legitimize an informal crossing route. 
Pi sadvantages 

• Crossing may be remote from desired travel 
directions of bicyclists and pedestrians. 

• May require extensive repair to permit safe 
conversion. 

• Culvert structure and pathway approaches are 
subject to flooding, thereby requiring Increased 
maintenance to keep free of debris. 

• Culvert may present dark and unplesant environment. 

• Culvert path is not usable during periods of 
high water, thereby necessitating an alternate 
route or cessation of travel. 

CASE STUDY REFERENCE 

Nos. 5,6,9,67 (see appendix) 



NOTE: To convert to metres multiply feet x 0.3048. 



131 



Existing 
bridge tie 






L Existing strln 



gers 



T 



•t.SMmln) 




8'(mln) 

pedestrian and 
blkeway width 



Graspable 
handral I — 



33"-36" 



New decking 



1 I 



tt 



■ ■•■■■ M 



Pedestrian 
rail 



11 



D 



Existing Railroad Trestle 
Section View 



Converted Railroad Trestle 
Section View 






Raised Floor Alternative 



Roadway 



ZL 



Earth fill 



Existing culvert 



:l 



z;:/z<::////^y///////< 



V V 



Raised Sidewalk Alternative 



Add protected light Removable 
fictures If necessary pedestrian rail 




Add reinforced concrete 
bike and pedestrian path 
to eel I 



Retrofitted Box Culvert - Section View 



Figure 22. RETROFIT PROJECT 3 - CONVERT AN EXISTING OVER OR UNDERCROSS I.NG 
TO EXCLUSIVE USE OF BICYCLISTS AND PEDESTRIANS 



132 




New 
pedestrian 
rail with 
graspable 
handrail _. 



i-M a »_ 



Posts or 
bal lard 



' I 5 ' 



(typ.) 




_»J 



New pedestrian 
ral I to protect 
bike/pedestrian 
from steep 
embankments 



Converted Highway Bridge 
Plan View 



Asphal tic 
concrete 
repaying - 



New 

pedestrian 
rail 



Existing 
concrete 
balastrade 



Graspable 
handral I 



33"-36" 



1 



4.5' (mln) 



Existing 
bridge deck 



Converted Highway Bridge 
Partial Section View 



Guide signs and 
warning signs for 
high water and 
clearance 




Potential at-grade crossing 
alternative for rainy weather 



for 



Blke/pedestrlan path 
thru box culvert 



J 



Highway 
overcrosslng 



Edge of 
pavement 




Retrofitted Box Culvert Structure - Plan View 

Figure 22. RETROFIT PROJECT 3 - CONVERT AN EXISTING OVER OR UNDERCROSSING 
TO EXCLUSIVE USE OF BICYCLISTS AND PEDESTRIANS (Continued) 



133 



condition treatments discussed here should be utilized to complement the 
prototypical design strategies presented earlier in this chapter, there- 
by completing the systematic analysis of the three grade crossing com- 
ponents. 

Basic Types of End Conditions . There are two basic categories of 
grade crossing end conditions associated with bicycle and pedestrian 
facilities. They are end conditions providing access to: 

• Grade separations shared with motor vehicles 

• Exclusive bicycle and pedestrian grade separations 

There are five primary locations where end conditions serving 
these grade separations occur. These are at: 

1« Intersection of roadways 

2. A continuation of a roadway 

3- Mid-block locations 

**• Intersection of exclusive pathways 

5« A continuation of an exclusive pathway 

From this point there are further degrees of catagorization which 
could include whether the bicycle and pedestrian facilities are located 
on one side, both sides or within a central median. Since most of the 
end condition treatments can be successfully applied to a variety of 
situations, the discussion below will be directed toward the more com- 
mon conditions of the five primary end condition locations. These 
basic concepts can then be applied to a particular situation at a given 
si te. 

General Concerns at End Conditions . Conclusions about end condition 
deficiencies drawn from the field studies and inspections can be grouped 
into three categories: Signs, Signals and Markings; Maintenance, and 
Design Features 

• Signs, Signals and Markings 

The most common end condition deficiency is a general lack of 
signing and marking pertaining to bicycle and pedestrian 
facilities and providing information to non-motorized travelers 
and motor vehicle drivers. Another common deficiency is lack 
of horizontal and/or vertical clearance between a sign post or 
sign and the pathway edge. 



13^ 



• Maintenance 

Preservation of sight distance is particularly important at 
end conditions, as is maintaining a clean and smooth pathway 
surface to facilitate transitions. Maintenance is a continuing 
need and where deficiencies exist for prolonged periods, the 
effectiveness and attractiveness of the facility is decreased. 

• Design Features 

Design related. deficiencies for end conditions typically pertain 
to features which are incomplete, such as lack of curb cuts, or 
facilities stopping at project boundaries regardless of con- 
tinuity needs or providing facilities only along one side of a 
roadway where two sided operations are preferable. 

Uniform Features . For the purpose of this discussion, it is 
assumed that a number of features are always included in the end con- 
dition treatments presented in the next section. These uniform features 
are as fol lows: 

• Minimum pathway widths of five feet (1.5M) for a one way path 
and eight feet (2.^M) for a combined bicycle and pedestrian path 

• Grades not exceeding 8.33 per cent 

• Curb cut and ramps installed where necessary to facilitate 
access to the grade separation approach 

• Pathway clearances to fixed objects of at least one foot 
horizontally and eight feet (2.^M) vertically 

• Sight distance which allows safe stopping distance for both 
bicycles and motor vehicles 

• Proper maintenance of facilities 

• Both pedestrians and bicyclists use the facility 

1. Intersection of Roadways . Roadway intersections are the most 
critical of all the end condition types because of wide variation of 
traffic control and design features combined with numerous travel pat- 
terns. 

• Traffic Control 



Traffic control elements applicable to the intersection and its 
approaches should be reviewed and modified based on current and 
potential traffic demands including volume and travel behavior 
anticipated as a result of over and undercrossing improvements. 



135 



Crosswalk locations should be confirmed and marked or deleted 
as necessary. Where there are crosswalk restrictions, they 
should be signed and physical barriers installed where 
appropriate to prevent usage. Intersection control should be 
reviewed and upgraded as required. This could include adding 
stop signs or installing bicycle and pedestrian actuated sig- 
nals. A pathway facility in a central median is a special 
application of intersection control needs. Lighting should be 
considered where it is not already in place. 

The pedestrian phase on existing signals should be reviewed to 
assure that timing is adequate for the type of user anticipated 
Audible tones during the walk interval could be considered 
where blind pedestrians are frequent. Guide signs should be 
coordinated to identify intersecting or directional changes 
of bike routes and signs designating separate or shared 
facilities for bicyclists should be installed. Do not enter 
signs should be posted to discourage wrong way travel on one 
way bicycle facilities. Pavement markings, such as messages 
and directional arrows, help to clarify proper usage. The 
pathway should be kept free of posts and poles wherever pos- 
sible. 

Where one sided bicycle and pedestrian facilities are used on 
the approach, extra care must be taken to provide delineation 
and signing which facilitates the pathway users ability to 
return to the existing street system, and to be properly 
oriented for continuing travel. Pedestrian and bicyclist 
behavior makes this task difficult because of the tendency 
for straight line travel. This is why space for bicycle and 
pedestrian travel is preferred on both sides of a roadway. 

Design Features 

Curb cuts and ramps should be constructed to provide full 
access to crosswalks even though the improvement project does 
not include the entire intersection. Curb cuts should be 
oriented so users will enter the crosswalk instead of being 
directed to a non-crosswalk area. Ample level space should be 
provided for pathway users to wait off the roadway prior to 
entering the intersection. 

Drainage facilities should minimize ponding in crosswalk areas, 
and drainage grates should not be located within a crosswalk. 
Drainage grates located within the travelway should be designed 
to be compatible with bicyclists and pedestrians. In certain 
situations, geometric design improvements could result in 
safer bicycle and pedestrian crossings. Minor revisions to 
traffic islands which restrict the intersection could facili- 
tate bicycle travel through the intersection. Removing high 



136 



speed turning lanes where not needed, or replacing a curved off 
ramp with a signalized T intersection where capacity would 
permit are two more examples of design improvements. 

2. Continuation of Roadway . This end condition presupposes that non- 
motorized bicycle and pedestrian travel is generally parallel to the road- 
way, and that there is no intersection with a roadway or other pathway. 
Therefore, there is normally no need for persons to cross the roadway 
at the end condition. Ideally, the same level of bicycle and pedestrian 
facilities provided on the approach would be continued, at least until 
the next intersection with a pathway or roadway. The least desirable 
situation would be to terminate the bicycle and pedestrian facilities 
at the end condition, thereby forcing users to directly enter the road- 
way, or to find their own path to continue their journey. 

• Traffic Control 



With a continuous bicycle and pedestrian facility there is 
usually no need to install traffic control devices since the 
end condition is not a major decision or conflict point. On 
occasion, however, signing may be useful to provide advance 
warning or guidance information regarding the approach to the 
grade separation or a nearby intersection. 

Where a bicycle path transitions from an off-street location to 
an on-street location, such as from a sidewalk to a shoulder 
or bike lane, signing and striping will be necessary to inform 
bicyclists and delineate space on the roadway. 

When a bicycle and pedestrian facility is terminated at the end 
condition, a major decision point is created. Depending upon 
the extent of travel and the degree of difficulty necessary 
for users to reach suitable bicycle and pedestrian facilities, 
advance informational signs placed at access points on both 
sides of the grade separation would be useful to inform poten- 
tial users of the discontinuity. 

Design Features 

Where a bicycle path transitions from off street to on street, 
it may require an elongated curb cut to accommodate the pathway, 
or a widened roadway which allows bicyclists to enter the street 
directly without requiring a change in their line of travel. 

Some of the problems with discontinuous facilities along a con- 
tinuation of a roadway were discussed under Traffic Control. 
Another concern would be where a facility on one side is term- 
inated while a continuous facility exists on the other side of 
a roadway. This may create a tendency for some persons 
"trapped" in this fashion to cross the roadway rather than con- 
tinuing along an unimproved route. Completion of the missing 
link, advanced warning signs and barriers are possible aids in 

such cases. 

137 



3. Mid-block Locations . At grade, mid-block crossings of roadways 
by bicycle and pedestrian facilities can be relatively close to an inter- 
section or remote as might occur in a rural or park setting. In both 
instances, the crossing is generally unexpected by drivers and, there- 
fore, requires special treatment to enhance safety. 

• Traffic Control 



A crosswalk should be installed in most instances to delineate 
the crossing. Centerl ine striping should be placed on the 
approaches for further emphasis. Advance warning signs should 
be installed on the roadway approaches and, at higher volume 
situations, the crossing may even require flashing beacons or 
bicycle and pedestrian-actuated signals. Lighting of the 
crossing should be considered. Parking restrictions should be 
adopted if necessary to preserve sight distance and facilitate 
accessibility to the crosswalk. 

Traffic control applicable to the pathway may range from nothing 
to advance warning signs, and/or stop signs or traffic signals. 
Pavement markings, such as messages, limit lines and striping 
patterns across the pathway, can be used to alert users of the 
crossing. Guide and directional signs are also important 
in identifying the route and alternative destinations. Posts, 
bollard or gates are sometimes required to prevent motor 
vehicles' use of the pathway. These barriers should be located 
on level areas far enough removed from the roadway so as not 
to interfere with crosswalk accessibility. 

• Design Features 

Ample level space should be provided for pathway users to wait 
off the roadway prior to entering the crossing. Special cir- 
cumstances may enable the street to be narrowed at the crossing, 
thereby increasing visibility relationships and decreasing the 
required crossing time. Where possible, pathways should be 
designed so that bicycle approach speeds are moderated prior to 
the crossing. This can be achieved by upgrades or curving 
alignment. Fencing or barriers may be necessary at the end of 
the pathway where space is limited to keep pathway users from 
entering the street directly. In such cases, extra space should 
be provided for turning movements to allow users to gain access 
to an offset crossing. Curb cuts and ramps, or smooth transi- 
tions are required on both sides of the roadway to assure com- 
fortable access to the pathway. 

k. Intersection of Exclusive Pathways . The intersection of exclusive 
pathways is the end condition to be considered next. They may occur in 
a remote area or fairly close to a street. 



138 



• Traffic Control 

Center! ine striping on the approaches to the intersection is 
useful since it visually emphasizes the intersection (a definite 
benefit at night) and helps users to maintain correct travel 
positions. Ample sight distance and geometric treatments usual- 
ly eliminate the need for yield or stop signs to assign inter- 
section priority. Although there may be special situations 
where constraints are such that these signs are needed. 
Occasionally advance warning signs denoting an intersection are 
useful. However, the most desirable signs at these pathway 
intersections are guide or directional signs providing informa- 
tion about alternative destinations. 

• Design Features 

Expanded intersections with curves between the pathways 
facilitate turning movements and circulation. Even a simple 
addition of a triangular section of pavement between two exist- 
ing 90 degree sidewalks provides a noticeable benefit. Where 
bicycle volumes are high, pathway intersections designed as 
traffic circles requiring merging rather than crossing maneuvers 
may be an appropriate solution. 

Fencing or other physical barriers should be used in areas 
where there are steep slopes, nearby traffic or activity areas 
which present a potential hazard to persons using the pathways. 
The design should minimize the possibility of heavily utilized 
shortcut routes being developed between pathways. Corrective 
actions could include either formalizing the route or restrict- 
ing its use if it is considered to be undesirable. 

5. Continuation of Exclusive Pathway . In this situation an exclu-_ 
sive pathway continues away from the grade separation without intersect- 
ing an adjacent pathway or a roadway. The normal continuity would be 
for the exclusive pathway to continue until it intersects with another 
pathway or roadway. 

• Traffic Control 



With a continuous bicycle and pedestrian facility such as this, 
there is usually no need for traffic control at the end condi- 
tion location. On occasion, however, signing may be useful to 
provide advance warning or guidance information regarding the 
approach to the grade separation or a nearby intersection. 
Pathway striping may also be continuous through the end condi- 
tion, or it may begin there and continue into the approach. 



139 



• Design Features 

There are usually no special problems with the end condition of 
the continuation of an exclusive pathway. 

7.3.5 Non-Structural Solutions to Crossing Problems 

Non-structural solutions are defined as those solutions that provide 
crossing access to non-motorized users without requiring construction or 
modification of structural features. In addition to the status quo or 
do nothing option, there are five categories of non-structural solutions. 
These include: 

Traffic control strategies 
Alternative routes 
Alternative travel modes 
New technology 
Land Use Planning 

Traffic Control Strategies . Most frequently used non-structural 
strategies involve signing, striping, and signals to change the rela- 
tionship between motor vehicles and the non-motorized user. Either some 
of the space on roadways previously devoted solely to motor vehicles is 
designated for use by the non-motorized, or motor vehicle drivers are 
directed to accommodate to the presence of the bicyclist and pedestrian. 

Restripe Vehicular Lanes . Vehicular lane width can be slightly 
reduced and the pavement restriped to gain space for the non- 
motorized, or the existing shoulder area itself may be sufficiently 
wide, and only require striping. While striping is often used to 
delineate bike lanes, the handicapped and other pedestrians may 
also benefit from this treatment, particularly if no other facili- 
ties are available. Additional signing and/or pavement marking may 
also be required to restrict parking or to further identify non- 
motorized space. 

Lane Reduction . Lane reduction is possible along under-utilized 
roadways. Field observations combined with capacity analysis 
should be undertaken to determine if such a strategy is applicable. 
Lane reduction could be permanent or a temporary solution allowing 
additional time for planning, funding and implementation of more 
permanent bicycle and pedestrian facilities. It may be possible to 
close a lane to vehicle travel during times of especially high non- 
motorized demand such as on a weekend in a recreational area. 
Cities such as San Francisco and New York close park roadways to 
motor vehicles at certain times thereby enhancing bicycle and 
pedestrian travel. While these may be localized opportunities, 
they deserve attention. Change from a two way to a one-way street 



]k0 



may also allow lane reduction without adversely impacting auto 
travel characteristics. Under special circumstances a one way 
street striped for two way bicycle travel as exists in Eugene, 
Oregon may be applicable. (See Figure 23.) 

Remove Parking . A restriction on parking all or part of the day 
can recover existing space for non-motorized travel use. This 
strategy largely applies to an approach, since parking is rarely 
allowed on a grade separation. 

Reversible Traffic Lanes . Reversible traffic lanes are a traffic 
management tactic which can be applied successfully in special 
traffic situations. Creation of a reversible lane may allow space 
formally used by a travel lane to be designated for non-motorized 
travel . 

Utilize Shoulders of Limited-Access Roadway . Such shoulders can 
be opened to bicycle (and perhaps pedestrian) travel in areas 
where alternative routes over other surface roads may be less 
safe. The California Department of Transportation has recently 
opened 175 miles of Interstate 5 in the San Joaquin Valley to 
bicyclists, for example. 

Create Auto Free Zones . Auto free zones include portions of 
streets where motor vehicles are prohibited for part or all of 
the day. This includes areas which are permanently auto free 
as well as temporary applications of that principle, such as on 
a weekend. Downtown Boston, Massachusetts, is an example where 
an auto free zone has been applied. A mall is a specialized 
example of an auto free zone. In Phoenix, Arizona, one-half of 
an arterial street between two popular parks is designated for 
bicycle traffic on Sundays during the high demand bike riding 
season. Here a temporary re-organization is achieved by plac- 
ing of traffic cones and temporary signing. 

Assignment of Primary Right-of-Way to Non-Motorized Users . Primary 
right-of-way can be given to non-motorized users so that motor 
vehicle drivers must yield to them. This could be in effect along 
the roadway, as well as at crossings, and would be most favorable 
where there are low travel speeds, narrow bridges or underpasses 
without pedestrian facilities, and frequent non-motorized users. 
Application would probably be most common in park or recreation 
areas. Special signing, would be required to alert users of the 
right-of-way relationships. 

Share Transit Lanes . One version of priority right-of-way is where 
bicycles are allowed to use a special bus lane therefore achieving 
priority over automobile drivers. This option is emerging as more 
and more attention is being given to enhancing the travel charac- 
teristics of urban mass transit. 



141 



Shoulder a 
potential for 
use on 1 imi ted 
access roadway 



Lane reduction 
from narrow 
two-way street 
to one-way 
with two-way 
bike traffic 





P r i ma ry 
right-of-way 
assigned to 
bikes 



Figure 23- SIGNING AND STRIPING 



142 



Install Activated Warning Lights for Tunnels . Provision of a 
signal and warning signing which when activated by bicyclists 
alerts drivers to the presence of bicyclists in the tunnel. Such a 
system was designed by the State of Oregon and is successfully in 
operation at several tunnels along Route 2. (See Figure 24.) 




Figure 2k. WARNING SIGN SYSTEM 

BIKE PRESENCE IN TUNNEL 



Sign or Install Other Devices at Pedestrian Crosswalks at Interchanges 
Ramp geometries in interchange areas are such that pedestrian 
crossings are difficult for approaching drivers to identify, even 
when they are striped. Some possible ways to improve the situation 
are as fol lows: 

Install a pedestrian crossing sign at or very close to the 
crossing. A supplemental arrow sign pointing down at the 
cross walk could provide extra emphasis. (See Figure 25.) 
Relocate a crosswalk obscured from the view of on-coming 
traffic to a more visible location. 

Install a quick response pedestrian activated traffic signal. 
Install flashing warning lights, actuated or continuous, or 
install rumble strips to supplement warning signing. 

While these strategies may have merit in special circumstances, 
crosswalk delineation and warning signing should be considered 
first. 



43 




Figure 25. CROSSWALK AND GUIDE SIGNING 



Provide Information and Regulatory Signing : 

Install informational signing to direct users to appropriate 
crossings or to provide information regarding route 
distance and destination. It is important that this type 
of signing provides a continuity of information. 
Install regulatory signing mandating use of certain 
facilities or directing change in travel direction for 
the non-motorized traveler. (Note: the presence of 
these signs does not necessarily insure user conformance). 
Detailed attention is required at transition areas 
between unrestricted and restricted use. Transitions 
should be logical and lead users to the proper route. 

Delineate Rest Areas . Place a simple stripe or mark on the pave- 
ment or adjacent wall or fencing to delineate the location of rest 
areas, thereby making it easier for persons to determine the distance 
between rest areas. 

Issue Facility Use Permits to Bicyclists . Require that a permit be 
obtained by bicyclists prior to being allowed to utilize a vehicular 
bridge too narrow for bike lanes. This technique is used success- 
fully in Eugene, Oregon, to enable qualified bicyclists to use a 
freeway bridge previously forbidden to all non-motorized travel. 

Improve Maintenance of Non-Motorized Facilities . Improved or more 
frequent maintenance is another non-structural technique which can 
enhance non-motorized travel. In some situations debris accumula- 
tion, particularly glass, can cause users to avoid the facility or 
to endanger themselves by using the vehicular lanes. Therefore, 
funds spent to construct access do not accrue the expected benefits. 
Ease of maintenance should be one of the principal considerations 
when designing facilities, thereby reducing features which contri- 
bute to the maintenance requirements. 

Alternative Routes . Lacking a direct crossing of a barrier, non- 
motorized travelers usually select the most convenient native route 
available. Sometimes travel can be made along the same general alignment 
that a structure would provide and in other instances it may entail a 
detour of some distance. Alternative routing may result in at-grade 
crossings or utilization of an adjacent grade separation. 

Provides satisfactory access . Depending upon route characteristics 
and length of detour, an alternative route may provide an entirely 
satisfactory service to the majority of potential users. There- 
fore, a new grade separation, though technically feasible, may not 
be required at least for some time. In other cases, a design 
barrier such as stairs may be bypassed if adversely effected users 
have a barrier-free alternative route along which they can complete 



145 



the same journey without excessive rerouting. installation of 
additional signing might be necessary to effectively guide users to 
and along alternative routes. 

Requires upgraded access . Conversely, alternative routes may lack 
continuity or accessibility, may expose bicyclists, pedestrians and 
the handicapped to excessive traffic conflicts or may be situated 
such that crossing opportunities require considerable detours for 
the majority of the potential users. The question then becomes 
whether the existing system should be upgraded or whether other, 
more direct, non-structural or structural solutions are more 
appropriate. 

Alternative Travel Modes . In some specialized instances, buses, vans, 
and transit trains can be used as an alternative crossing method. 

Provide Regularly Scheduled Transit . Regularly scheduled transit 
can provide service across structures which do not have facilities 
for non-motorized travel. Buses with wheelchair lifts are especial- 
ly helpful to certain groups of handicapped persons. Buses can 
also be equiped with bicycle-carrying facilities such as racks or 
a trailer providing separate holding facilities. Bay Area Rapid 
Transit (BART) allows bicyclists to obtain a permit to carry their 
bicycles onto the last car of the train during off-peak times. 
Ferryboats also can accommodate bicyclists. (See Figure 26.) 

Provide Special Transit Service . Special transit service can be provided 
across structures where there are no facilities for non-motorized 
travel or to serve persons not able to utilize a grade separa- 
tion. Various combinations of fixed route and demand- responsive 
systems are possible, ranging from those provided by transit companies 
to institutional or group-sponsored services. 

It should be noted, however, that for short trips waiting time may 
exceed the travel time necessary for a person to utilize an alternate 
route unless transit service is frequent or particularly convenient for 
individual needs. 

New Technology . Improvements in the wheelchairs currently utilized 
by handicapped persons appears to be an area where new efforts could 
increase mobility potential. 

Devices to Enable Wheelchairs to Mount Curbs . Devices could be 
developed which permit wheelchair users to mount curbs which do not 
have wheelchair ramps. This might be achieved by designs which 
inflate a cushion which "absorbs" the curb and raises the wheel- 
chair up to a level even with the top of the curb. Another concept 
to achieve a similar effect would be a device composed of rods or 
"feet" operated by means of hydraulics and gearing. This device 
would be designed to raise the wheelchair and then "walk" it over 

the curb or, conceivably, up a short flight of stairs. 

146 



Shuttle bus 
with bike rack 




Van with 
trai ler 
serving as 
commuter 
bicycle 
shuttle 



Figure 26. UTILIZING ALTERNATIVE TRAVEL MODES 



1*7 



Wheelchair Power . Development of improved power sources and gear- 
ing systems for motorized wheelchairs could improve reliability 
and range of mobility. 

Better Braking Systems Can Be Developed . Wheelchair braking sys- 
tems can also be improved, particularly for the manual wheelchair. 

Wheelchair Leveling Devices . A device to level a wheelchair in 
motion would be helpful to lessen the effect of grades or cross 
slopes on wheelchair occupants, and could simulate a level rest 
area for wheelchair users stopped on a grade. 

Land Use Planning . Considering facilities for the non-motorized 
in future land use, transportation, and recreational facility plans, 
could eliminate some barriers. 

Facilities Location . School, shopping, recreation and work trips 
can be oriented along pedestrian and bikeways, which in turn are 
designed to minimize conflicts with motorized traffic. Attempts 
can be made to locate certain types of pedestrian and bicycle 
traffic generators (such as schools) on the same side of potential 
barriers (freeways, railroad tracks) as residential dwellings. 

However, the idea of locating housing for the disabled close to 
activity centers is not compatible with the "mainstreaming" con- 
cept. People should have a choice of living areas without forced 
segregation because of being disabled. While the convenience of 
having key activities near home cannot be denied, it should not 
lessen the effort directed toward reducing accessibility barriers 
elsewhere throughout the system. 

7.3.6 Design Innovation and New Techniques 

The results of this research study indicate that there is no immen- 
ent technological breakthroughs that will drastically change the develop- 
ment of non-motorized facilities on overcrossings and undercrossings. 
However, as briefly outlined in Chapter 5, there are a number of modi- 
fications or enhancements of existing methodology and procedures which 
are innovative, and which may have application to specific problems. 

This section of the Final Report is intended to familiarize design- 
ers and other interested individuals with innovative and unusual designs 
not commonly used. The concepts and features presented represent ex- 
amples of actual existing projects, as well as untried ideas, and is 
intended to stimulate consideration of unconventional approaches as well 
as the more commonly and strategic. 

Unusual Locations and Facility Configurations . In some instances, 
changing the placement of a non-motorized facility on a structure, 
slightly altering standard design procedures or improved utilization 
of existing structures can provide the solution to a particular cross- 

148 



ing problem. Some of the techniques that are illustrated have appli- 
cation to both new and retrofit project situations. 

• Non-Motorized Facility Location 

Placement of a pedestrian path and bikeway within the truss 
portion of the structure above a highway bridge is a concept 
which may be applicable where expansion of the deck is imprac- 
tical. The structural members will usually be strong enough to 
support a supplemental pathway deck. However, there may be 
some difficulty overcoming grade differentials unless hilly 
topography allows the pathway to enter at a high level. 

Underneath bridge structures with girders which are at least 
8.5 feet (2.6m) there is an opportunity to replace cross- 
bracing with horizontal bracing at the top and bottom, thus 
creating an opening large enough to accommodate a pathway. 
While lighting, surveillance, ventilation, and access are 
special design concerns, the treatment is an alternative to 
consider where deep structural girders are present. 

On bridge designs utilizing concrete box girders with depths 
of at least 8.5 feet (2.6M), it may be possible to use the open space 
within the box for a pathway. To improve surveillance and 
decrease the tunnel effect, openings could be cut in the outer 
wall. While interior lights would probably be required, wall 
openings would be helpful. As with other underneath or aerial 
strategies, access would most likely required special design 
features. 

A pathway structure could be hung from the bottom of an 
overcross ing. Care would have to be exercised to maintain 
clearance requirements beneath the overcrossing. Access to 
the pathway would be another design problem. 

It is possible to utilize the lower crossing bracing connecting 
overcrossing piers as support for a pathway surface. In this 
case, the pathway would be well below the main structure and 
in the open, with the bridge deck serving as a canope. The 
low level pathway would be easier to gain access to where 
adjacent ground levels are also low. Clearance requirements 
beneath the structure might be a problem. (See Figure 27.) 

At one site in Bakersf ield, Cal i fornia, a walkway canti levered 
from a parking lot to an office building on the other side of 
a railroad. Without this unique treatment, parking lot users 
would have a considerable detour to reach the regular walkways 
through the undercrossing. A pedestrian overcrossing alter- 
native spanning the railroad would have been considerably more 



^9 



Canti levered 
walkway from 
underpass 
abutment 




Regional trail 

ut 1 1 izing 

abandoned 

rai 1 road bridge 



Figure 27- UNUSUAL FACILITY CONFIGURATIONS 



150 



expensive, as well as requiring users to overcome a height 
differential roughly double that of the canti levered under- 
crossing treatment. (See Figure 27,) 

Tunnel construction is expensive and, therefore, space is 
rarely available to retrofit non-motorized facilities within 
the tunnel wall. However, it may be possible to recover 
enough space outside of the regular travelway in areas used 
for ventilation or previously occupied by a pilot tunnel. 
Ventilation, security, lighting, and access are some of the 
problems which must be solved. 

Utilization of Existing Structure 

Abandoned highway bridges, tunnels and railroad trestles 
represent a potentially valuable resource for use as part of 
bicycle and pedestrian systems. Often only minor modifica- 
tions will make them suitable for use by the non-motorized. 
When a decision is made to abandon such facilities, ways of 
utilizing the structures, rather than demolishing them, should 
be explored. 

Bridges for Areas Subject to Flooding 

In North Dakota, a bridge built over a river with a wide 
flood plain was designed to be lifted onto adjacent temporary 
higher piers to avoid being washed away during high water. 
Cranes are utilized to lift the bridge at times of anticipated 
flooding. This technique allowed development of small bridges 
serving a regional bikeway, rather than requiring much larger 
and more expensive structures capable of withstanding flood 
conditions. An alternative plan for the smaller bridge scheme 
was to have the bridge designed with a lift to move up and 
down on its own supports. Though technically feasible, this 
was a more expensive plan and therefore was not implemented. 

Another flood plain design strategy is to construct bridges 
which are extraordinarily sturdy. Then, if they are washed 
off their abutments, they can be retrieved and re-set with- 
out being irreparably damaged. 

Differential Sidewalk Settlement 

Differential settlement at the point where the approach path or 
sidewalk meets a structure is a common problem. Repairs usually 
consist of placement of a wedge-shaped asphalt or concrete patch. 
This treatment reduces the problem, but it may require additional 
attention as settling continues. On new structures, the problem 
can be corrected for concrete walks by designing the abutment so 
the approach sidewalk rests on it rather than the adjacent soil. 
This creates a bridging effect spanning the area most susceptible 
to settlement. Asphalt walks are flexible and do not have the 

151 



bridging strength that concrete does. A short section of concrete 
walk could be used to provide the transition to the structure, or 
additional care should be taken on subgrade preparation to minimize 
the degree of settlement. ( See Figure 28. ) 



Problem 



Sol ut ion 








! 

4 i 










\ 


> 








y 


// Sidewalk 


Structure 




1 
V 


f """ """""" 



Figure 28. DIFFERENTIAL SIDEWALK SETTLEMENT 

Driveways Intersecting Sidewalks 

Driveways intersecting sidewalks oftentimes create uneven surfaces 
across the entire sidewalk; othertimes the driveway only partially 
penetrates the sidewalk. While this leaves a level area for bicyclists 
and pedestrians, it may steepen the driveway slope to a point where 
it adversely impacts drivers. There are several alternative approaches 
which could be used to reduce this problem. (See Figure 29) 

Create a widened sidewalk to allow the full travel surface to 
bypass the area affected by the driveway slope. 

Design the driveway slope to be completed before intersecting 
the sidewalk. This means that the sidewalk, at least near the 
driveway, must be set back from the edge of the roadway rather 
than being adjacent to the curb 1 fne. 

Design the sidewalk to slope down to meet the driveway at a 
consistant grade and at gentler slopes (maximum 8.33 percent) 
than those now used which have varible slopes some of which 



52 



A 



^SScbi. 



f~ 



Sidewal k 



TUPP" 



A 



B 



W' 



Driveway 
Total Impact Partial Impact^ 



W 



B C 
S 4_ 



SSSSSa. 



W*r : 



c 



D 
4_ 



^i W 



Bypassed 



Plan View 



ifflpp*' 



D 
_4 



Offset 



A-A 



X 



B-B C-C 

Cross Section 



D-D 



Driveway 




It 

Uniform Gentler Transition 



Curb 




Uniform Slope 
(10% Max.) 



Section E-E 



F 







Driveway 








= 













— 




. ■ 


















• •■ F 










_T 



r 



Driveway 



J 



^ 



Ramp^ N Ramp 

Section F-F 



Figure 29. SIDEWALK/DRIVEWAY RELATIONSHIPS 



53 



exceed 15% for short distances. A special case of this type 
treatment is where a major driveway is designed 1 i ke a street 
and the entrance sidewalk width is ramped down to meet the 
roadway grade. 

Rest areas are often parts of ramped approaches to structures. For 
new facilities the rest area can be a special constructed feature. 
Two important considerations are whether the rest area should be in 
the travel way or adjacent to it, and the spacing between rest 
areas. Retrofiting rest areas to existing structures may prove 
difficult because of established grades and features. Some alter- 
natives to traditional rest area designs are illustrated in Figure 
30 and can be described as follows: 

Hold bars imbedded in the wall which allow persons to grasp 
them or to clip themselves onto as a rest stop. 

A bar imbedded into the wall which could be pulled out to a 
position perpendicular to the direction of travel. 

Slots in the pavement parallel to the direction of travel 
could be positioned in such a fashion as to allow a wheelchair 
user to insert one wheel. The slot would then serve as a 
wheel stop, allowing the wheelchair user to stop and rest. 
Slots could be positioned along both sides of the ramp at 
intervals of 10-20 feet (3- 1—6. 1 M) , so as to serve the varying 
needs of wheelchair users. Care should be taken to locate the 
slots close enough to the side of the pathway so as not to 
pose a potential danger to bicyclists. In some cases the 
slots would be located adjacent to the pathway in narrow 
widened areas. A self-cleaning design or maintenance will be 
necessary to maintain proper slot depth. 

Small blocks (about 1 inch (25.4 MM) high) positioned at the 
edge of ramped pathways or immediately adjacent to the wall or 
fence might be an effective wheelblock for a wheelchair. This 
treatment should not be used where a sidewall or fence are 
lacking, since bicyclist and pedestrians would then have the 
freedom to occupy the entire path and the blocks may constitute 
an obstruction. 

Sitting places can be developed as indentations into the 
structure sidewall, or the wall section can be thickened or 
cant i levered to form a seat. 

"Vee" shaped niches can be constructed in the walls where 
wheelchair users could stop perpendicular to the wall while 
still retaining their original direction of travel. 

A folding seat could be installed which is normally flush with 
the side walls until used. It would fold out perpendicular to 

154 



© 

Holding 
Bar 




Deck 









Slot 



N 



^ 



© 



Rai sed 
Block 




Deck 



©Indented Sitting Place 
for new structure 



"Vee" niche 

for new structure 



© 




Plan View 




Plan View 



// S i dewa 1 1 



S i dewa 1 1 




Wall 
Thicken ing 



© 

ding /+• 



Folding 
Sea 





Cant i levered Alcove 
in non-struc 



Canti levered Alcove 
in Fencing 




Figure 30. CONCEPTUAL REST AREA ALTERNATIVES 



55 



the wall and a spring- loading device would return it to its 
original position after use. The seat could be utilized 
equally well on solid or fenced walls. A disadvantage to 
this design would be its potential susceptibility to vandalism. 

Sitting spaces can be developed in fence walls by construction 
of an alcove. This applies to both new and retrofit situations 
The position of the seat could be level or could parallel the 
ramp grade. 

• Increased user awareness through improved user education can also 
pay dividends. For instance, successful techniques for ascending 
and descending ramps could be explained to handicapped persons. An 
example would be for a wheelchair user to park perpendicular to the 
ramp slope thereby creating a stable "rest area" when needed where 
no special physical feature exists. 

• Dissemination of information regarding accessible routes and modes 
of transportation would increase the users' ability to select the 
transportation system elements most suited to their travel needs 

Recycled Materials . Most grade crossing projects are constructed 
with new materials; however, there are circumstances where use of recy- 
cled materials can produce a final product which is both functional and 
cost-effective. 

• Railroad flat cars are often up for sale once their useful life 
is over. Structural properties of a flat car make it suitable to 
serve as a bridge. It can be placed on abutments and new decking, 
handrails can be added as required. (See Figure 31 •) 




Figure 31. RAILROAD FLAT CAR BRIDGE 
156 



Trailer truck beds are another recycled source of bridge-like 
structures which may constitute a special application. (See 
Figure 32.) 




Figure 32. TRAILER TRUCK BEDS (POTENTIAL BRIDGE) 



• Barges may have some applications in providing a foundation for a 
floating structure, although their potential use does not appear to 
be as widespread as that of railroad flat cars or trailer truck 
beds. 

• Large size culvert pipe could serve as support columns for a bicycle/ 
pedestrian bridge. 

• Salvaged bridge beams from replaced structures represent a poten- 
tial source of building material which may be particularly suited 
to support decking for an exclusive bicycle/pedestrian bridge. 
Timber beams, planking and utility poles may also have similar 
application, under special circumstances. In some cases entire 
structures have been salvaged, intact, and made available for use 
at other sites. 

Imaginative reuse of material available at little or no cost can 
mean an economically justified improvement, where traditional approaches 
would result in solutions which are too expensive to implement. 



157 



Construction Techniques . Improvements in construction techniques 
relating to bridges and tunnels can reduce the cost and increase the 
feasibility of installing facilities for non-motorized travelers. Many 
of these techniques are mature, having been used during the construction 
of major projects over several years. Their application to bicycle and 
pedestrian facility construction has been limited or untried. Some 
potential techniques include the following: 

• Structural and other project elements can be manufactured on-site 
using "Factory" techniques. This allows more efficient use of 
full time employees and maximizes benefit derived from workers 
brought in to perform specialized tasks. 

• Standardized design for similar facilities can minimize engineering 
design effort, facilitate fabrication, simplify erection and make 
maintenance more efficient particularly if standardization of 
features occurs at a number of different sites within the same 
jurisdiction. 

• Prefabrication of major structural elements can minimize the need 
for storage space and erection time. This is of prime importance 

in urban areas where traffic delay or detour can be of major concern. 

• Simple and standarized erection procedures can be developed for use 
by relatively unskilled crews. This could allow public works 
employees in a jurisdiction to assemble certain structures without 
the need of highly paid outside specialists. 

• Maximize use of local materials to minimize transportation costs. 

• Use grouts to stabilize soils and to exclude water from excavations, 
making it more economical to construct underpasses in difficult 

soi 1 condi t ions. 

• Pipe jacking is a mature construction process. This technique 
could be used for jacking underpasses for bicyclists and pedes- 
trians as an alternative to tunneling or cut and cover-type 
construction. It might also be possible to apply the vibration 
techniques used in some pile driving applications to jacking, 
perhaps further enhancing its usefulness. 

Alternative Methods of Conveyance . In some special instances 
providing other means of conveyance may be a more satisfactory solution 
to crossing a barrier than constructing special bicycle, pedestrian, or 
handicapped facilities. They may be particularly useful for accommodating 
handicapped persons. Some of these possibilities are as follows: 

• Elevators, while commonly used in buildings, are rarely applied to 
grade separations, unless they are associated with a transportation 
terminal. It appears that where vertical separation to be overcome 



158 



is great (16 feet (k.Sh) or more), that the construction cost of 
stairs supplemented by an elevator are cost-competitive with a 
solution providing only ramps at a 10 percent grade or less. 
Elevators can be erected in internal or external configurations and 
take little space. Maintenance, operating costs, user access, and 
security are all issues which must be addressed before a final 
decision can be made. However, it appears that there may be 
situations where elevators should be seriously analyzed as a 
potential solution. 

• Escalators and moving sidewalks again are common to circulation 
systems within buildings and along high-use corridors, such as are 
found within transportation terminals or at major spectator sports 
complexes. However, it should be noted that space and maintenance 
requirements appear to discourage use of escalators as a viable 
solution for overcoming steep grades at all but a very few special- 
ized locations. In addition, certain handicapped persons may have 
difficulty with access and egress to escalators on grades. 

• Stair climbers are track-mounted seats which provide the user 
mechanical assistance as an alternative to a stairway. The typical 
application today is in residences to serve the elderly or to 
overcome a long steep grade from the garage to the house. This is 
a proven system which may have application at certain grade 
separations. 

• The principle employed in a typical automobile jack may be applic- 
able, o-r at least merit further investigation. It potentially 
could result in a manually operated elevator device. Similarly, 
the hydraulic jacking principle is another area worthy of explora- 
tion. 

7.3.7 Improved Designer and User Understanding 

The findings of this study indicate that the planning, design and 
operation of non-motorized facilities on over and undercrossings can be 
considerably enhanced if technical personnel and facility users achieve 
a better understanding of the subject matter. This section discusses a 
number of possible educational and information communication techiques 
which can help in this regard. 

Planners and Designers . In some cases, the requirements and 
characteristics of non-motorized travelers have not received sufficient 
attention from those responsible for planning, design and maintenance of 
under and overcrossings. Technical staffs have to become more sensitive 
to the needs of bicyclists, pedestrians and the handicapped. Once this 
necessity of including non-motorized travelers in the process is 
recognized, then a means must be found for insuring that the operational 
consequence of standard designs is properly understood. Two of the 



159 



techniques utilized in carrying out this study can help achieve both 
these objectives. These were the site evaluation visits by technical 
staff and the use of a panel made up of members with varying disabili- 
ties to evaluate facilities for handicapped travelers. 

The techniques developed to evaluate the six sites in detail were 
successful and should be considered for further use. They facilitated 
orderly accumulation of site specific information in a relatively short 
time. The use of two engineers with varying backgrounds, in this case 
civil engineering and traffic/transportation, helped to broaden the 
observational base as did the dual approach of independent and combined 
evaluation. While there was a good deal of overlap between basic 
problems, it was evident that each site often possessed unique features 
which must be individually considered if a successful facility is to be 
built. The techniques used in the field observation increased the 
awareness of design consequences. They also can be exercised in the 
office during plan conceptualization and review to identify potential 
problem areas susceptible to location, design, construction and maintenance 
deficiencies. The important consideration is for the designer to view 
the facility as conceived from the different viewpoints of each of the 
three user groups. 

Data in this report will help to increase the designer's level of 
awareness and sensitivity to problems, but it should not be considered 
as a final answer. Preferably, this report can be used as a building 
block in a continuing process of learning and advancement of the state 
of the art. 

Where possible, evaluations should be made after construction of a 
facility to identify features which perform especially well or those 
which cause problems. While it may be difficult to devote large blocks 
of time to these efforts, it should be possible to glean useful infor- 
mation from routine maintenance and inspection activities as well as 
citizen input expressed in letters or telephone calls. These data would 
provide additional insight into local experience which could form the 
basis for modifying design standards and policies to be even more 
sensitive to the needs of bicyclist, pedestrians and the handicapped. 
Periodic preparation of brief summaries of these findings for internal 
circulation or for publication in technical journals would even 
further enhance the benefits gained from local experience. 

Users . Increased user awareness through improved education and 
communication should be a goal of agencies and organizations respon- 
sible for over and undercrossing facilities intended to improve the 
accessibility of bicyclists, pedestrians and the handicapped. 

Initially information should be circulated to potential users by 
means of various media such as newspapers, pamphlets, flyers, newsletters, 

radio and television. Direct contact with user group organizations and 



160 



agencies is also desirable. The information should be addressed to all 
users with emphasis on special features such as might be required by 
certain handicapped persons. 

The means of crossing the barrier should be explained and a 
description should be provided regarding special features, alternatives, 
if available, and the relationship of the facility to the adjacent 
transportation system. For instance, a map showing location of wheel- 
chair ramps would be helpful to a person requiring ramp access. 

Knowledge of the transportation system will increase the user's 
ability to select the transportation routes most suited to their 
travel needs. 

7.3.8 Handicapped Considerations 

Some particularly noteworthy additional points pertaining to handi- 
capped travelers on over- and undercrossings are summarized below. 

The handicapped are a heterogeneous group with varied mobility 
limitations and needs, extending over the following range: 

1. Persons fully able to utilize any facility accessible to bicycles 
and pedestrians. 

2. Persons requiring certain features such as ramps and handrails 
but who otherwise can manage to utilize regular bicycle and ped- 
estrian faci 1 i ties. 

3. Persons requiring special features such as low ramps, rest areas, 
or elevators to be able to use a grade separation. 

k. Persons who would not be able to use the facility regardless of 
the improvements provided. 

To accommodate the first two categories of handicapped persons, 
little or no extra costs are involved in improving or building a struc- 
ture beyond what would be required for standard bicycle and pedestrian 
facilities. The third category may require substantial design modi- 
fication and costs, while the fourth group of persons would not benefit 
at all from construction of an over- or undercrossing, even one acess- 
ible to other handicapped persons. 

Once the likelihood of usage by the above-defined groups of handi- 
capped persons is identified, it is possible to select the range of 
design elements which most closely serves these needs. 



161 



Structural versus Non-Structural Solutions . It appears that many 
over- and undercrossings specifically designed and built to accommo- 
date the handicapped will still be a physical or psychological barrier 
to certain persons. For instance, excessively long ramps are a deter- 
ent to usage even though grades are less than the recommended national 
standards. For example, the desirable maximum grade of 5 percent 
creates a 67 percent longer ramp than an 8.33 percent grade ascending 
the same vertical separation. 

Where the vertical separation is 20 feet (6.1M), such as required 
over a freeway, the difference in ramp length between a 5 percent 
and an 8.33 percent grade is a 400 foot (121.9M) long ramp compared 
to a 2*t0 foot (73. 2M) long ramp. If both ramps to the overcrossing 
are similar, total ramp travel is lengthened by at least 320 feet 
(97. 5M) or 67 percent. Persons in manual wheelchairs or with muscle 
control or breathing difficulties would probably not be able to use 
such a facility unless elevators were provided. 

Therefore, it should be re-emphasized that non-structural solu- 
tions to crossing situations are valid and must be thoroughly evalu- 
ated as an alternative or a supplement to a structural solution. For 
example, it may be found that an alternative mode of transportation 
such as provided by rerouting bus service or an alternative route 
crossing made accessible by installing wheelchair ramps and traffic 
control devices can be more viable and cost-effective solutions, pro- 
viding access to a larger proportion of the handicapped population 
than would have benefited from an over- or undercrossing. 

Identification of Handicapped Needs . As noted in the previous 
section, one area which seems to be promising is the use of a panel 
of handicapped advisors to identify travel needs of the disabled. The 
advisory panel can be of valuable assistance during the planning,, 
design and decision-making processes. Handicapped panel members can 
provide insight to site specific needs based upon their own perspectives 
as well as being spokespersons for an advocate group. To be most 
effective, the advisory panel should be organized officially with a 
specific set of goals and responsibilities so their participation fits 
in smoothly into the design and decision-making process. The use of 
local active handicapped persons with varying disabilities for panel 
members is highly recommended. 

In addition, the panel could logically shoulder the responsibility 
of alerting the entire handicapped community to the project being con- 
templated, as well as assuring that input is presented not only from 
activist groups and individuals but from handicapped persons who, 
although they require improved accessibility, would normally not par- 
ticipate in the public input process. 



162 



Implementation Priorities . The question of where and when handi- 
capped facilities should be implemented is important. It includes 
consideration of site specific as well as system factors. It is 
obvious that an over- or undercrossing made accessible to the handi- 
capped is usually of little use if the surrounding transportation 
system is not also accessible. Therefore, with regard to over- and 
undercrossing situations, areas rather than just facilities should be 
made accessible. This means that more attention should be focused on 
the demand tributary area to identify potential barriers and to develop 
mitigating measures. In some cases, such as between compact clusters 
of activity, a preferred route within an area made accessible might 
satisfy the needs (61). 

Priorities for implementation of facilities to enhance handi- 
capped accessibility should be based upon density of existing and 
anticipated use by the handicapped. Based upon discussions with 
handicapped participants in this study, the following order of prior- 
ity was developed: 

Central shopping, services and employment districts. 
Special purpose facilities. 

Satellite shopping. 

Residential with high percentage of handicapped. 

In practice, a balanced program of expenditures in each area 
will probably result, but with emphasis based on usage by the handi- 
capped. 

Other Considerations. It should be remembered, however, that 
even if the ideal design or plan is conceived, it will be necessary to 
monitor construction to assure that features are completed properly. 



As a general observation, it is believed that as travel barriers 
decrease the travel behavior of the handicapped will approximate that 
of the general public. 

7.3.9 Current Design Strategies - Adequate and Inadequate . 

Examples of both adequate and inadequate crossing treatments were 
identified as a part of this study. These are summarized below, classi 
fied according to their presence on the structure, approach or end 
condition and the following subject groupings: 

1 . Sidewal ks 

2. Railing and Fences 

3. Structure 

k. Traffic Control 
5. Maintenance 



163 



Treatments in each of these groups were segregated into Adequate or 
Commendable Design Strategies (Table 13) or Inadequate or Undesirable 
Design Strategies (Table 1*t). Adequate or commendable treatments 
include many features related to sidewalks. For example, this included 
the use of curb cuts; increased width; removal or relocation of street 
furniture and plantings; separation of motorized and non-motorized 
travel paths; and improved drainage. Another large category included 
various innovative structural treatments. Inadequate or undesirable 
design strategies again included sidewalks as a major category. 
Deficiencies in width, grade and drainage surface were the most common. 
Problems dealing with structures ranged from lack of facilities to 
building structures in wrong locations. Suggestions for corrective 
action have been made and are included opposite each inadequate or 
undesirable design strategy listed in Table Ik. 

The data in Tables 13 and Ik are presented so that designers have 
an opportunity of quickly reviewing both the good and the deficient treatments 
found elsewhere in actual practice and thereby be more aware of treatments 
which may help to improve the specific site under consideration. 



164 



Table 13. Current Design Strategies 
Adequate or Commendable 







Component 


i Adequate or Commendable Design Strategy 


Structure Approach En 


X 


X 


Sidewalks on one or both sides. 






X X 


Curb cuts on approaches and end conditions. 






X 


Inclusion of ramps versus stair only access. 




X 


X 


Conscious effort to minimize gradient. 




X 


X X 


Increased width for shared facilities. 




X 




"Heated" structures to minimize effect of snow/ice. 




X 


X 


Design elements such as grating to minimize snow 
effect and effect of debris. 




X 


X 


Barriers between sidewalk users and travel lane. 




X 


X X 


Providing satisfactory horizontal clearance for 
pathway users. 




X 


X 


Rest areas on approaches and structures which enable 
certain groups of handicapped persons to utilize the 


r -0 






structure where before there was no space designed 








for persons of limited stamina to rest. 


2e 


X 


X 


Creation of points of interest, such as sitting 








areas, playgrounds, view vistas, etc., adjacent to 


02 






structure, such as at approach or within a vehicle 
ramp. 






X 


Construction of stair and ramp access to structure 
to allow users a choice of which mode best satis- 
fies thei r needs. 




X 


X 


Placing street furniture trash recepticles, etc. 
along side of pathway rather than on pathway, there- 
by decreasing the effective travel width. 




X 


X 


Separation of motorized and non-motorized travel 
paths and crossings, such as by taking advantage of 
natural or manmade topography. New town and green 
belt corridors exhibit many successful examples. 






X 


Specially designed "ramps" to allow bicycles to be 
rolled or pushed up stairways. 






X 


Paving or formalizing "short cut" routes forged over 
time by users. (This only occurs if the "short cut" 
route provides safe service.) 






X 


Construct drainage ditches along toe of embankment 
slope to catch run-off before it flows across path- 
way. This also indicates treatments that will 
probably have less problems with erosion. 



65 



Table 13. Current Design Strategies Adequate 
or Commendable (Continued) 





Components 


d Adequate or Commendable Design Strategy 


Structure Approach En 


X 


Revised fencing height where bicyclists are antici- 
pated to at least h.S feet (l.^tM). 


s 
a; 


X X 


Provision of sight barriers to preserve privacy of 
adjacent residents. These barriers have a dual 
function as a noise barrier, which helps residents 
as well as blind users. 




X 


Placing handrails along approaches to structures, 
especially where stairs are involved. 




X 


Carry usable shoulder through structure for safety 
reasons as well as serving bicyclists. 




X 


Upgrading bridges and providing space for non- 
motorized needs. 




X 


Retrofitting existing structures, thereby improving 
service to non-motorized users. 




X XX 


Concentration of effort at "critical" sites. 




X XX 


Willingness to design special facilities to serve 
uniquely local characteristics. Example: Provision 
of Fisherman's Bridge adjacent to sidewalk carrying 
pedestrians over a regular highway bridge. 


as 

Si 
Co 

Si 
"-0 


X 


Spanning difficult or scenic area, by unusual treat- 
ments. 

• "Flexible" wooden bridges over marshy area. Un- 
stable soils create differential settlement/ 
heaving. Pile supports are designed to enable 
deck jacking. 

• Removable structure built in a flood plain 
designed to be (raised) removed by crane on threat 
of flood. 

• Trail bridges over-designed to be very structur- 
ally strong to enhance durability during floods 
where bridge is "swept" away or dragged to one 
side. 

• Canti levered pathways along the top portion of a 
paved drainage channel, allowing a trail to be 
established between two cities through an out- 
wardly unfeasible route. 




X XX 


Carrying non-motorized improvement from the struc- 
ture to the approach and end treatment to establish 
continuity of route. 



66 



Table 13. Current Design Strategies Adequate 
or Commendable (Continued) 







Components 


d Adequate or Commendable Design Strategy 


Structure Approach En 


X 


X 


Utilization of abandoned RR right-of-way, as well as 
refurbishing RR bridges to serve for non-motorized 
crossings. 








• Pave over wooden deck 

• Create new wooden deck overties 




X 


X 


Use abandoned highway bridges with minor pavement 
repair to serve non-motorized. 






X 


Increase embankment width to serve as partial or full 
support for pathway leading to the structure. 




X 


X 


Create multi-purpose "pathways" serving non-motorized 
demands, as well as facilitating emergency vehicle 
access. For example, a centrally located bicycle/ 
pedestrian facility designed to allow emergency 
vehicles to use the path to gain access to distressed 
motorists. 




X 


X 


Increase bridge span length to allow a pathway to be 
constructed on the embankment underneath. 


ft; 


X 


X 


Special use bridges/overpasses to separate various 
types of travel . 


Ei 

ft; 
to 






• Earthen overcrossing with corregated metal pipe 
undercrossings separating horse travel at race- 
track from pedestrian and vehicular movements. 




X 




Developing multi-functional structures serving ex- 
clusive non-motorized needs, as well as carrying 
utilities across the barrier. 




X 


X 


Combining structural aesthetic with function. 




X 


X 


Innovative use of recycled materials, such as steel 
beams, timber and fill material to improve cost- 
effectiveness and enhance the visual characteristics 
of the faci 1 i ty. 




X 


X 


Utilization of flood plainsduring dry season, rather 
than building a structure or as an alternative until 
a structure can be financed. 


o 

Ei 


X 


X X 


Traffic controls at street or ramp crossings, stop- 
ping vehicles, thereby allowing pedestrians and 
bicyclists a better opportunity to cross a street 
without conf 1 icts. 


"o 
H 

^: 

ft; 

E-i 




X X 


Designs channelizing users onto structures, rather 
than allow opportunities to cross the barrier at- 
grade. This could be accomplished by alignment or 
construction of physical barriers. 



167 



Table 13. Current Design Strategies Adequate 
or Commendable (Continued) 



Component 



Structure Approach End Adequate or Commendable Design Strategy 

X Use of existing one-way traffic bridges to accommo- 

date two-way non-motorized travel. 

X XX Making non-motorized travel a priority on streets 

during certain hours of the day or days of the week. 

X XX Actuated traffic control allowing non-motorized 

travel to compete with motor vehicles. 

X Striping of shoulder area and gore to facilitate 

bicycle weaving maneuvers. 

X Require bicyclists to dismount and walk where design 

is substandard. (For example, at certain points on 
the Golden Gate Bridge.) 

X XX Marking, retrofitting or designing drainage inlets 

to reduce hazard to cyclists. 



X XX Lighting of structures, approaches and intersections. 

X X Overlaying steel decking plate with layer or membrane 

of "rough" paving to serve as anti-slip surface 
during wet conditions. This 'is not effective, how- 
ever, with snow and ice accumulation. 

X Applying preservatives to a new Glulam wooden bridge 

to reduce problems caused by persons writing on the 
wood and then cleaning it, only to have preservative 
added absorbed more by the cleaned areas. The result 
is a "permanent" disfiguring. 

X XX Landscaping that does not encroach upon the pathway, 

thereby requiring maintenance to preserve the quality 
of travel . 

X Design light standards to be attached on the structure 

outside of the railing or fencing. 



68 



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17A 



GLOSSARY 



ARCH CROWN - The highest point or vertex of an arch. 

BALUSTRADE - A coping or handrail on a bridge parapet supported by 
small pillars. 

BEAM GUARDRAIL - A rail to prevent motor vehicles from accidently 
leaving the roadway. Constructed of a steel beam with a "W" shaped 
cross section mounted on wood, concrete, or steel posts. 

BICYCLE - A device propelled exclusively by human power upon which 
any person may ride, and having two tandem wheels. 

BIKEWAY - Any trail, path, part of a highway or shoulder, sidewalk, 
or any other construction designated for bicycling use. 

BOX GIRDER - A steel or reinforced concrete girder having a hollow 
rectangular cross section. 

CANTILEVER - A beam or girder fixed at one extremity and free at the 
other. 

CHORD - One of the main structural members which lie along the top 
or bottom edge of a truss framework. 

COLUMN BENT - Two or more columns at a common support location tied 
or connected at the top so as to form a frame supporting a bridge, 
overpass, or trestle deck. 

CORRUGATED STEEL PLATE ARCH - Large curved structural plates with 
corrugated surfaces that can be bolted together to form arch shaped 
structures; often used for the construction of tunnels, culverts, and 
small underpasses. 

DESIGN STANDARD - These are criteria which serve as a means of 
determining what a thing should be, thereby enabling construction of 
features which have consistent qualities even though they may be con- 
structed at a different time or place. 

DESIRABLE MAXIMUM - As applied to design criteria, this defines the 
level which should not be exceeded if at all possible. However, there 
may be situations where the desirable maximum must be exceeded and 
may reach the maximum acceptable design level if the facility is to be 
considered feasible. 

DIFFERENTIAL SETTLEMENT - Unevenness or vertical height differences 
between parts of the same structure or adjacent structures caused by 
varying settlement of the supporting soils. 



175 



GLOSSARY (Continued) 



DOUBLE TEE BEAM - Two side-by-side rectangular cross section reinforced 
concrete beams joined at the top by a common section of reinforced con- 
crete slab so as to appear as a double "T" in shape. 

EXPANSION JOINT - A joint between two parts of a structure to allow 
these parts to expand with temperature variance without distorting 
lateral ly. 

FASCIA - A wide, flat member of a framework supported by columns. 
(The vertical surface of a bridge deck.) 

GLU LAM - Structural grade glued laminated timber assemblies of 
selected and prepared wood laminations bonded with adhesives. A wide 
variety of shapes, including curved, and sizes are available. These 
are often used where a combination of structural strength and aesthetics 
is considered desirable. 

GRADE SEPARATION - Vertical isolation of travel ways through use of a 
structure, so that traffic crosses without interference. 

GUIDELINE - An indication or an outline of a suggested course of 
action which within the context of this report is seen as being flexible 
and allowing variation depending upon the circumstances, rather than 
being a rigid mandate. 

GUSSET PLATE - A steel plate used for connections, as in a steel truss 
connecting the members framing into a joint. 

HANDICAPPED - For purposes of this report "handicapped" includes those 
individuals who use wheelchairs; have impaired hearing or vision; walk 
with difficulty, with or without prosthetic aids; have diminished 
agility, stamina, or reaction time: are of unusual body size, including 

those who are very small or large; have upper extremity impairments, 
including those with arm, hand, and neck impairments. The definition 
may encompass the elderly, very young individuals, and those with 
temporary injuries or impairments, in addition to those who are 
permanently disabled. 

JOIST - A horizontal beam of timber or steel used with others as a 
support for a floor and/or ceiling or a deck. 

MEDIAN - The portion of a divided road or highway separating the 
traveled ways for traffic in opposite directions. 

MUD SILL - The lowest horizontal timber block or the like serving as 
a foundation of a wall, house, small bridge, or other structure, usually 
placed in or on the ground. 



76 



GLOSSARY (Continued) 



NAILER - A timber that has been fastened to a steel or other metal 
beam or structural member to allow other wood boards or timbers to be 
nai led to i t. 

NEW JERSEY TRAFFIC BARRIER - A reinforced concrete barrier with a 
sloped surface shape that returns motor vehicle wheels to the roadway 
when struck in a "sideswipe" type collision. 

NON-MOTORIZED TRAVELER - A person whose mode of transportation is by 
other than a motorized vehicle; includes bicyclists, pedestrians, and 
handicapped persons. For the sake of this report, a motorized 
wheelchair user is included within this classification. 

PARAPET - A low wall along the edge of a bridge or overpass or a 
roof. 

PEDESTRIAN - A person whose mode of transportation is on foot. 

PLATE GIRDER - Large steel plates that have been riveted or welded 
together to form a girder. 

POLICY - A defined course of action adopted as being expedient. 
Typically a policy would be followed without requiring additional 
research to substantiate its validity. An example of a policy would 
be to always provide shoulders along a limited access highway. 



PRESTRESSED CONCRETE - Concrete poured around strong steel cables, 
wires, etc., which are kept under tension until bonded to the con- 
crete, and when the tension is released it produces compressive stress 
and greater strength in the concrete. 

REINFORCED CONCRETE - Concrete in which steel bars (reinforcement) 
are embedded in order to provide increased strength. 

RETROFIT - The modification of an existing over- or undercrossing 
in some manner, either structurally or otherwise, to facilitate its 
use by bicyclists, pedestrians, or the handicapped. 

ROADWAY - That portion of the highway included between the outside 
lines of the sidewalks, or curbs and gutters, or side ditches, includ- 
ing the appertaining structures and all slopes, ditches, channels, 
waterways, and other features necessary for proper drainage and pro- 
tection. 

SAFETY CURBS (BARRIER CURBS) - Relatively high and steel faced curbs 
designed to inhibit or discourage vehicles from leaving a roadway. 

177 



GLOSSARY (Continued) 



SHOULDER - The portion of the roadway contiguous with the traveled 
way for accommodation of stopped vehicles, for emergency use, and for 
lateral support of base and surface courses. 

SHY DISTANCE - The distance between the edge of a bikeway or the 
edge of a motor vehicle travel way and any fixed solid object. There 
is also a psychological aspect of shy distance where users select a 
travel zone on a pathway depending upon the space available and their 
assessment of how far they must be away from an obstacle to be com- 
fortable. 

SPALLED CONCRETE - Pieces of concrete that have chipped or splinter- 
ed off; in reinforced concrete this is often caused by corrosion and 
subsequent expansion of the embedded reinforcing steel. 

SPANDREL - The space between the haunches and the road decking of 
an arch. 

SPANDREL WALL - A wall constructed upon the extrados (top surface) 
of an arch. 

STRINGER - A long, horizontal member in a structural framework. 

STRUT - Any light structural member or long column which sustains 
an axial compressive load. 

SUPERELEVATION - Raised outside edge of a roadway curve for the pur- 
pose of overcoming the force causing a vehicle to skid when maintain- 
ing speed. Often this is called a "banked curve." 

TRAFFIC BARRIER - A fence, rail, wall, or other device erected in 
a roadway to prevent movement of motor vehicles from or into an area. 

TRAVELED WAY - The portion of a roadway for the movement of vehicles, 
exclusive of shoulders and auxiliary lanes. 

TREATED WOOD OR LUMBER - Wood piles, beams, or other structural or 
non-structrual members that have been treated with preservative chem- 
icals, such as coal tar creosote, to prevent decay due to exposure to 
water, weather, marine organisms, or insects. 

TRUSS - A combination of members such as beams, bars, ties, or the 
like, arranged usually to a triangle or collection of triangles join- 
ed together so as to form a rigid framework, and used in bridges 
(bridge truss), roofs (roof truss), etc., to give support and rigid- 
ity to the whole or part of the structure. 



78 



GLOSSARY (Continued) 



VIADUCT - A structure consisting of a series of short span bridges in 
line supported on intermediate piers carrying a roadway or railroad 
across a wide, deep valley. 

WARRANTS - A warrant is one means by which the relative need for a 
facility can be evaluated. Warrants provide guidance in the decision- 
making process. The fact that a warrant is met is not conclusive 
evidence that a facility is needed, since the review of warrants is 
only one step within the needs assessment process which considers all 
pertinent facts. 

WEB - A solid or open system connecting the chords or flanges of 
structural members, such as a steel plate connecting the top and bot- 
tom flanges of a steel beam. 

WIRE MESH RAILING - A pedestrian or bicycle barrier railing consist- 
ing of a steel or wood framework with extruded or other metal mesh 
closing the open parts of the frame. 



179 



REFERENCES 



1. Swan, S., et al , De Leuw, Cather S Company. Effective Treatments 
of Over and Undercrossings for Use by Bicyclists, Pedestrians and 
the Handicapped; A Literature Review . Report No. FHWA-RD-78-142. 
Prepared for U.S. Department of Transportation, Federal Highway 
Administration, Offices of Research and Development, Washington, 
D.C., 1980. 

2. De Leuw, Cather S Company. Effective Treatments of Over and 
Undercrossings for Use by Bicyclists, Pedestrians and the Handi- 
capped; Internal Working Paper 1: State of the Art . May, 1978. 
Unpubl i shed. 

3. De Leuw, Cather & Company. Effective Treatments of Over and 
Undercrossings for Use by Bicyclists, Pedestrians and the Handi- 
capped; Internal Working Paper 2: Warrants and Design Selection 
Criteria . September, 1978. Unpubl ished. 

4. De Leuw, Cather & Company. Effective Treatments of Over and 
Undercrossings for Use by Bicyclists, Pedestrians and the Handi- 
capped; Internal Working Paper 3: Design Strategies . October, 
1978. Unpublished. 

5. De Leuw, Cather & Company. Effective Treatments of Over and 
Undercrossings for Use by Bicyclists, Pedestrians and the Handi- 
capped; Internal Working Paper 4: Site Evaluations . November, 
_£ ________ _____________ _______ 

6. Swan, S. Treatments of Over and Undercrossings for the Disabled: 
An Early Report on the State of the Art . Paper presented at the 
Transportation Research Board Annual Meeting; Washington, D.C. 
January, 1978. 

7. Swan, S. Assessments of Treatments of Over and Undercrossings 
for Use by the Disabled: Florida Experience . Paper presented 
at the MAUDEP Seminar. Chicago, Illinois. July, 1978. 

8. Marchand, B. "Pedestrian Traffic Planning and the Perception of 
the Urban Environment: A French Example." Environment and 
Planning , September-October, 1 97^, pp. 491-507. 

9. Baerwald, E. "The Pedestrian." Traffic Engineering Handbook . 
Washington, D.C: Institute of Traffic Engineers, 1965, 
Chapter 4. 

10. Maring, G.E. "Pedestrian Travel Characteristics." Highway 
Research Record J»06 (1972): 14-20. 



80 



11. Navin, F. P. D. and Wheeler, R. J. "Pedestrian Flow Character- 
istics." Traffic Engineering 39 (1969): 30-36. 

12. Kelly, J. J. Piccadilly Circus Pedestrian Study . Research 
Memorandum 429. London, England: Greater London Council, 
Department of Planning and Transportation, 1974. 

13. 1 Flaherty, C. "Movement on a City Center Footway." Traffic 
Engineering and Control , February 1972, pp. 434-438. 

14. Older, S. J. "Movement of Pedestrian on Footways in Shopping 
Streets." Traffic Engineering and Control 10 ( 1 968) : 160-163. 

15. Fruin, J. J. Pedestrian Planning and Design . New York, New 
York: Metropolitan Association of Urban Designers and Environ-, 
mental Planners, 1971. 

16. Pushkarev, Boris and Zupan, M. Jeffrey. Urban Space for Pedes- 
trians . Massachusetts Institute of Technology Press, 1975. 

17. Scott, W. G. and Kagan, L. S. A Comparison of Costs and Benefits 
of Facilities for Pedestrians . Washington, D.C.: U.S. Depart- 
ment of Transportation, Federal Highway Administration, 1973. 

18. Hutchinson, B. G. and Morrall, J. F. "Some Characteristics of 
Pedestrian Circulation Within the Central Business District." 
Proceedings of the 1969 Canadian Good Roads Association Conven- 
tion , Edmonton, Alberta, Ottawa, 1970, pp. 533-544. ~~ ' 

19. Sandels, Stina. "People in Traffic." International Federation 
of Pedestrians Bulletin , December 1969, pp. 1-8. 

20. Hoel, Lester A. "Pedestrian Travel Rates in Central Business 
Districts." Traffic Engineering , January 1968, pp. 10-13. 

21. Levinson, Herbert S. "Pedestrians in the Urban Environment." 
Seminar on Planning, Design and Implementation of Bicycle/ 
Pedestrian Facilities, San Diego, 197*5" ! Proceedings. Berke 1 ey , 
California: University of California, Institute of Transporta- 
tion and Traffic Engineering, 1974, pp. 157-192. 

22. Smith, Daniel T. , Jr. Safety and Locatlonal Criteria for Bicycle 
Facilities: Final Report . Prepared for U.S. Department of 
Transportation, Federal Highway Administration, Offices of 
Research Development, Washington, D.C., 1975. 

23. Crain & Associates (eds.). Transportation Problems of the Trans- 
portation Handicapped: Volume - The Transportation Handicapped 
Population, Definition and Counts . Prepared for U.S. Department 
of Transportation, UMTA. Washington, D.C., 1976. 



18 



2k. Abt Associates. Accessibility of the Metropolitan Washington, 

D.C. Public Transportation System to the Elderly and Handicapped: 
Executive Summary . Prepared for Department of Transportation, 
Office of Environmental Affairs, Washington, D.C, 197^. 

25. Arthur D. Little. Employment, Transportation and the Handicapped , 
1968. 

26. Crain and Associates, Portland Handicapped and Elderly Survey: 
Special Report (Summary) . Menlo Park, California, 1976. 

27. Falcocchio, John C. and Cantilli, Edmund J. Transportation and 
the Disadvantaged: The Poor, the Young, the Elderly, the Handi- 
capped. Lexington, Massachusetts: Lexington Books, 197^. 

28. Roberts, Diane C, "Pedestrian Needs: Insights from a Pilot 
Survey of Blind and Deaf Individuals." Publ ?c Roads 37 (1972): 
29-31. 

29. Jones, Michael A. Draft — Accessibility Standards, Illustrated . 
Springfield, 111.: Capi tal Development Board (1977). 

30. Templer, John A. "Provisions for Elderly and Handicapped Pedes- 
trians." Seminar on Planning, Design and Implementation of 
Bicycle/Pedestrian Facilities, San Diego, 197^ . Proceedings. 
Berkeley, California: University of California, Institute of 
Transportation and Traffic Engineering, 197^, pp. hhk-k^O. 

31. Abt Associates. Transportation Needs of the Handicappea: Travel 
Barriers . Springfield, Virginia: NTIS, 1969. 

32. U.S. Department of Health, Education and Welfare. First Report 
of the Architectural and Transportation Barriers Compliance Board , 
Washington, D.C, 197*t. 

33. Peat, Marwick, Mitchell & Company and RTKL Associates, Inc. A_ 
Manual for Planning Pedestrian Facilities . Report Number 7^~5. 
Prepared for Federal Highway Administration, Offices of Research 
and of Development, Washington, D.C: NTIS, 197^. 

3**. Technical Council Committee 5-HH. "Informational Report: Direct 
Connecting Ramps To and From Major Terminals." Traffic Engineer- 
ing k5 (1975): 32-39. 



35. Andrews, Basil. "Do Signs and Markings Always Protect the Ped- 
estrian?" Traffic Safety , April 1973, p. 11. 

36. Duff, J. T. "Road Accidents in Urban Areas." Journal of the 
Institute of Highway Engineers, May 1968, pp. 61-73. 



182 



37. Fee, Julie Anna. "Highway Research Program to Enhance Pedestrian 
Safety." Pedestrian Bicycle Planning and Design Seminar , San 
Francisco, 1972. Proceedings. Berkeley, California: University 
of California, Institute of Transportation and Traffic Engineer- 
ing, 1973, pp. 148-151. 

38. Constantine, Prof. T. "Justification for Subways and Bridges for 
Pedestrians in Urban Areas." Proceedings, 10th International 
Study Week in Traffic and Safety Engineering . London, England: 
OTA, 1971, PP. 95-97. 

39. Breines, Simon and Dean, William J. The Pedestrian Revolution: 



Streets Without Cars . New York, New York: Vantage, 1974. 

40. Ashworth, Robert. "Delays to Pedestrians Crossing a Road." 
Traffic Engineering and Control , July 1971, pp. 114-115. 

41. Benepe, Barry. "Pedestrian in the City." Traffic Quarterly , 
January 1965, pp. 28-42. 

42. Traffic Engineering Study Group. "Pedestrian Subways." Traffic 
Engineering s Control (1961): 740-41, 749. 

43. California (State) Department of Public Works, Division of High- 
ways. "Bridge Railings (7-211.10)." Highway Design: Manual of 
Instructions . Sacramento, California, August 1, 1975. 

44. Herms, B. "Pedestrian Crosswalk Study: Accidents in Painted 
and Unpainted Crosswalks." Transportation Research Record 406 
(1972): 1-13. 

45. Johnson, R. T. "Freeway Pedestrian Accidents: 1958-1962." 
Highway Research Record 99 (1965) 274-280. 

46. Jacobs, Jane. "Do Not Segregate Pedestrians and Automobiles." 
Architects Year Book 12 . London, 1968. 

47. Hamill, James P. "Planning and Development of Bikeway Systems." 
Urban Land 32 (1973): 9-15. 

48. Smith, Daniel T. , Jr. Safety and Locational Criteria for Bicycle 
Facilities, User Manual - Volume 1: Bicycle Facility Location 
Criteria: Volume II: Design and Safety Criteria . Prepared for 
U.S. Department of Transportation, Federal Highway Administra- 
tion, Offices of Research and Development. Springfield, 
Virginia: NTIS, 1976. 

49. Lott, Dale F. and Lott, Donna Y. "Effect of Bike Lanes on Ten 
Classes of Bicycle-Automobile Accidents in Davis, California." 
Journal of Safety Research, December, 1976, pp. 171-179. 



183 



50. Templer, J. A. "Stairways, Some Physiological Responses and 
Behavioral Patterns." Pedestrian/Bicycle Planning and Design 
Seminar, San Francisco , 1972. Proceedings. Berkeley, California: 
University of California, Institute of Transportation and Traffic 
Engineering, 1973. 

51. American Association of State Highway and Transportation 
Officials. Guide for Bicycle Routes . Washington, D.C.: 
American Association of State Highway and Transportation 
Officials, 197^. 

52. American Association of State Highway and Transportation 
Officials. A Policy on Design of Urban Highways and Arterial 
Streets - 1973 . Washington, D.C.: American Association of State 
Highway and Transportation Officials, 1973. 

53. City of Chicago, Department of Streets and Sanitation, Bureau of 
Street Traffic Design Standards Manual , Chicago, 1976. 

5**. California (State) Department of Public Works, Division of High- 
ways. Bridge Planning and Design Manual. Volumes I -IV. Sacra- 
mento, Cal ifomia, (updated periodically) . 

55. JHK & Associates. Planning Guide for Development of Pedestrian 
and Bicycle Facilities . Prepared for the Wisconsin Division of 
Highway Safety Coordination. San Francisco, 1977. 

56. Institute of Traffic Engineers. "Pedestrian Overcrossings - 
Criteria and Priorities." Traffic Engineering , October, 1972, 
PP. 3^-39, 68. 

57. Washington (State) Department of Highways. Pedestrian Crossing , 
State Route 5 and *tth Street in Blaine , Olympia, Washington, 
1970. 

58. Seattle Engineering Department. Priority Study, Pedestrian Over- 
passes , September, 1968. 

59. Batz, Thomas, et al. Pedestrian Grade Separation Locations - A 
Priority Ranking System . Volumes I and II. Trenton, New Jersey: 
New Jersey Department of Transportation, Bureau of Operations 
Research, 1975. 

60. Braun, R. L. and Roddin, M. F. Benefits of Separating Pedes- 
trians and Vehicles NCHRP Project 20-10. Menlo Park, California, 
Stanford Research Institute, 1975. 

61. Templer, John. Development of Priority Accessible Networks, Provisions 
for the Elderly and Handicapped Pedestrians , FHWA-IP-80-8 . 

62. Oregon State Highway Division. Bikeway Design . Salem, Oregon, 
197^. 

18** 



63. ANSI, INC. American National Standard Specifications for Making 
Buildings and Facilities Accessible to and Usable by, the 
Physically Handicapped . New York, New York, 1961 (revised 1971). 



64. 



Burgi, P. H. and Gober, D. E. Bicycle-Safe Grate Inlets Study 
Volume I - Hydraulic and Safety Characteristics of Selected Grate 
Inlets on Continuous Grades . Prepared for the U.S. Department 
of Transportation, Federal Highway Administration, Offices of 
Research and Development, Washington, D.C., June 1977. 

65. State of California Department of Transportation, Planning and 
Design Criteria for Bikeways in California . Sacramento, Calif- 
ornia, June 30, 1978. 



185 






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186 



APPENDIX B 



CASE STUDY SUMMARY AND IDENTIFICATION NUMBER 



Est, Usage 



Number 



LOCATION 



1 o 



-3 C = C 

D n iz z 



COMMENTS ANO FEATURES 



1 Nogales, Arizona 

2 | Austin, Texas over' 

the Colorado River 

3 Dover, N. H. 
k Swanzey, N.H. 

5 Calamine-Plattevil le 
Wisconsin 

6 Okobo j i , I owa 

Glenwood Springs 
Colorado 

8 Eugene, Oregon 
(Ferry St. Bridge) 

9 Montgomery Co. 
Maryland 

10 Peachblossom t, 
Trippe Creek, MO 

1 1 Jefferson County 
Oregon 

12 Rlckreal, Oregon 



13 Arlington County, 
Vi rginia 

\k Culpepper County, 

Virginia 

15 Bland Co. , VA 

16 Tazewell Co. , VA 

17 Giles Co., VA 

18 Westminister, 
Cal i fornia 

19 Vandal ia, Ohio 

20 Eugene, Oregon 

21 Pismo Beach, CA 

22 Hampton, New 
Hampshi re 

23 Henrico Co, VA 

Ik Alexandria, 

VI rginia 

25 i Pearl City 

| Oahu, Hawa i i 
I 

26 Stockton, 
Cal i fornia 

27 Plantation, 
Florida 

28 Anchorage, Alaska 

29 Fairbanks, Alaska 



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X H L L L U 



X M , L H L ! U One side sidewalk 

Deck replacement with prestressed concrete beams 
Reconstruction to BEGIN SPRING 1978 

Widen and protect sidewalk 

Cantilever 3' wide sidewalk both sides 

Conversion of existing railroad trestle 
PLANNED FOR 1978 

Converstion of existing railroad trestle. 
Expected 1978 

Cantilever new sidewalk on one side. 

X H H M L U X Construct new access ramp from bridge to park. 

Rehabilitated old structure as bikeway; Concrete 

X I - H:M L R Patching, Repairing guardrails, repaving. 

X MM L L R Removed balustrade and curb; install new railing 

Construct 6 1 wide walkway on one side of bridge 
i X 1 M : — " M L R connecting to footpath to river 

Construct 8' wide sidewalk. -Remove existing curb, 
fence, and barrier rail 

Construct 5' cant i levered walkway on one side 

Construct 3' 10" clear width cantilevered sidewalk on one side. 

Cantilever 5' sidewalk from one side. 

Cantilever 5' sidewalk from one side. 

Cantilever V10" sidewalk from one side. 

Construct a parallel bridge to make *t lanes plus 2 
sidewalks to conform with approaches ( NOT YET BUILT ) 

Construct 12' bike/ped way on one side ( NOT YET BUILT ) 

Widened embankments for new k ' sidewalk 

Widen existing bridge and ramp to accommodate 8 1 wide 
bike/ped path 

Widen embankment, relocate guardrail, construct sidewalk 
and cantilever walkway on structure 

Cantilever sidewalk on one side. 

Connected walkway under overpass to tunnel under 
tracks as alternative to putting sidewalks on bridge 

Fenced and Curbed existing wooden plank vehicle bridge. 

To be constructed 1978. Construct bike/ped bridge over 
river. Glulam Beams, serves mobile homes. 
Non-skid coating on deck. 

Construct bike/ped bridge over canal serves as access 
L U from parking lot to ballfield § school. 

L U Construct bike/ped bridge over creek; Glulam Beams 

L U 1978 construction . Bike/ped bridge over creek; use of 
: salvaged beams; flat bridge 72' long. 



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187 



APPENDIX B 

CASE STUDY SUMMARY AND IDENTIFICATION NUMBER (Continued) 

1 — : — ; 1 — r — : — — 

Est. Usage 



^Jurrber 



LOCATION 



:.'*.'■ *J 3= -* 

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3. 1. "2 2 

•j : S E 



COMMENTS AND FEATURES 



30 

31 
32 
33 

34 

35 
36 

37 

38 

39 

40 

41 

42 

43 
44 

45 
46 

47 

48 

49 



Champaign County 
Ohio 

Los Altos, CA 

Los Altos, CA 

Fargo, North 
Dakota 

Eugene, Oregon 



Keene , New 
Hampshi re 

Marinette, 
Wisconsin 



Sunnyvale, CA 

San Clemente, 
Cal i fornia 



Tempe, Arizona 

Pompano Beach, 
Florido 

Miami, Florida 



Sacramento, CA 

San Francisco, 
Cal i fornia 



Portland, Oregon X 

Eugene, Oregon X 

Med ford, Oregon X 

Loch Haven Reser- 
voir, Maryland X 



Delaware County, 
Ohio 

Palo Alto, CA 



M L 

- M 

- L 

- M 



- M 

- M 



H H 
H - 



5' walkway on one side of bridge. Gravel approaches. 
ML R State park nearby. Dam site. 

ML U Glulam Bridge over creek serves school and trail. 

M L U Arched Glulam Bridge. Along one side of Fremont Blvd. 

Prefabricated steel bridges built on flood plain. 
M L U X Can be raised during high water. Serves regional trail, 
parks, college. Conpleted Spring 1978. 152' long 

M L U Prestressed concrete beams. 528' long. Connecting to 
river bank trails. Complete Feb. 1978. Deck widened 
at piers for benches. 

Bike/ped bridge 155' long over Ashuelot River. 
ML R Recreational. Underconstruct ion Fall 1978 . 

New bridge with 9 -foot sidewalk for bike/ped on one side. 
M L U Supplemented by special fisherman's bridge. Some problems 
with approaches. 

L L U X i Central bike/pedway/emergency access road over Columbia 
River 6000' long. 

M L U X Bike/ped bridge/shared with utility. 667' long. 
Benches at piers. Autz-en Bridge. 

L L R Reinforced concrete bridge over Bear Creek. Serving 
trail. B% grade. Super elevation on curve. 

Bike/ped bridge together with traffic bridge on one side. 
Pave two way approaches separated by barrier from travel lane. 

Walkway on one side of the bridge separated by concrete 
L L R barrier. Alum Creek Reservior. 

M ; L U X Canti levered bike/ped way off from a drainage canal. 
Connects two neighborhoods. 

Bike/ped bridge over 101. Designed with rest areas. 

TO BE BUILT . Slopes to 15%. State architect recommended 
deletion of handicapped feature since alternative flat 
crossing was close by. 

Two 10' sidewalks included on both sides of new bridge. 

Helical ramps to overcrossing structure. Steep ramps. 
ML U Serves school . 

M L U Ped/bike overpass. Long ramps connecting neighborhoods 
severed by freeway. 

H i L U Underpass 90 foot Armco arch 

Helical open ramp connecting parking lot to United Airlines 
H L U X maintenance facility. Heavy use during shift changes. 
10.6% grade. 11 foot wide. Warning sign 



- M 
M L 
H L 

- H 

- M 

M i M I 

ML 

- M 

- M M L : U X 

- MM L U ! 
H M M : L U 



50 Anchorage, Alaska X 

51 Anchorage, Alaska X 

52 Anchorage, Alaska X 

53 Anchorage, Alaska X 

54 Anchorage, Alaska X 



- M M L U 

H M M I. U 

H M , M L U 

H M M L U 

H M M L U 



Underpass Armco superspan 85' long 13'9" wide. 

Bike/ped overpass 7' wide 140' long over Northern Lights 
Boulevard. 

Underpass Armco Superspan 92' long; 15' interval for 
1 ight ing. Serves trail. 

90' long Glulam Overpass. Stairs. Connects bike paths. 

Glulam beams. Bridge 5' clear distance between handrail. 
Switchback ramp. IN PLANNING STAGES. ; \ 



! h 



188 



APPENDIX B 

CASE STUDY SUMMARY AND IDENTIFICATION NUMBER (Continued) 

1 , , , 1 , 

Est. Usage 



Number LOCATION 



<U I "J 



o u r; m 

— « o Z> 

~ U JU "3 "C 

Ci ' — o ^ c 

•> . aa c_ , = — 



COMMENTS AND FEATURES 



55 
56 

57 
58 

59 
60 

61 

62 

63 
6*. 

65 

66 

67 

68 

69 
70 
71 

72 



Col umbus, Ohio X 
Columbus, Ohio X 



Frankl in County, 
Ohio X 

Wyoming, Michigan X 



Louden, New 
Hampshire X 

Austin, Texas X 



Keene, New 
Hampshi re 

Arl ington, 



H L M L ' U X 



H M ML U 



H M M L U 
H M M L R 



M M M L R 
H M L L U X 



M M M L R 



Vi rginia 


X 


H 


M 


M 


L 


U 


X 


Cuyahoga Co, Ohio 


X 


H 


L 


L 


L 


U 




Portland, Oregon 


X 


H 


M 


M 


L 


U 




Polk County 
Oregon 


X . 


i M 


M 


M 


L 


R 




Alexandria, 
VI rginia 


X 


H 


L 


M 


L 


U 




Rte. 183 Randolph 
Rd. Maryland 


X 


! 
H 


M 


M 


L 


R 


X 


Eugene, Oregon 


X 


M 


L 


L 


L 


U 




San Bernardino 
Cal i fornia 


X 




L 


L 


L 


U 




Eugene, Oregon 


X 




H 


; H 


L 


U 





Hayward, California X 



Pleasanton, 
Cal i fornia 



M M L U 



M : L H L U X 



Aluminum arch 120' long. Stair access along a school 
route over Hamilton. 

Prestressed concrete box beam construction. Connects 
school and residential neighborhood over Rte. 71. 
10$ slopes. 

Overpass of Rte 315. Children using culvert drain pipe 
to reach school. 550' long, 7'6" wide between handrails. 

Underpass Armco pipe deleted from plans for fear of 
vandal ism. 

Underpass created for trail path by lengthening highway 
bridge. 

Construct bikeway thru interchange. 2 bridges (8'wide) 
modify guardrail, handrails, signing, striping, wooden 
planking. UNDER CONSTRUCTION 1977 . 

Bike/ped 8' wide on one side of new bridge (268 ' long) 
Separated by barrier. PLANNED 1977-78 . FAP project.' 

Structural steel box truss. Ramp and stair on same side. 
Checker plate/grating floorway. Residential to school. 

Bridle path on one side of structure. 

Bike/ped overcrossing of 1-5. 155' long. Access ramps 
are perpendicular to structure. 

Bike/ped overcrossing 200' long 10' wide. 5.72% grade. 
Spanning Highway 22. 

Bike/ped ramp overpass. High screening. Compromise 
location. Ugly. 

Modified box culvert to create elevated pathway. 
UNDERPASS . 

Overpass built to cross railroad tracks. Overdone and 
not wholly useful. 328' long. 10% grade. At $66,000 
it was cheap. 

Ped/bike path 8' wide on one side. 1600' long. 
Separated by barrier. Under RR. UNDERPASS 

Underpass , precast prestressed concrete box under RR 
connecting to Autzen Bridge. 

Underpass . Explored alternative pathway alignments and 
selected bike lane on both sides rather than one side 
off street alternative. Under RR. 



Ped/bike/vehicle underpass of Horse overcrossing. 



189 



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192 



APPENDIX D 



DETAILED SITE EVALUATION DESCRIPTIONS 

The following descriptions present detail data relating to back- 
ground, structure and costs of the six evaluation sites summarized pre- 
viously in Chapter 6 of this report. 



PALO ALTO, CALIFORNIA 

As noted earlier, the James A. Hawkinson Memorial Bicycle/Pedes- 
trian Bridge spanning Adobe Creek at the easterly end of Wilkie Way in 
Palo Alto, California, was selected as a pilot study site. The pilot 
study served to field test proposed procedures and techniques to be used 
to gather data for the other five site evaluation studies. The Palo 
Alto site was chosen because it was well -used and was an innovative 
design treatment of a new, exclusive bicycle and pedestrian facility 
connecting residential neighborhoods. 

Background 

The City of Palo Alto is an active bicycling and pedestrian community, 
due in some part to the presence of Stanford University. The City has a 
bicycle facility master plan, and is actively constructing bicycle and 
pedestrian facilities. 

One of the barriers to travel in Palo Alto is Adobe Creek, a flood 
control channel. Adobe Creek runs in a northeast-southwest direction 
through most of Palo Alto. In the area bounded by the Southern Pacific 
Railroad tracks, El Camino Real, and San Antonio Road, Adobe Creek separates 
two residential neighborhoods from each other. The nearest crossing is on 
El Camino Real, a very busy major arterial. The decision was made by the 
City of Palo Alto to construct a bicycle and pedestrian bridge over Adobe 
Creek to connect the two residential developments. 

Structure 

At the site chosen, Miller Avenue and Wilkie Way, deadend at the 
Creek, offset from each other by a distance of 300 feet (33-^). A 
bicycle/pedestrian walkway was constructed partially cant i levered over 
the edge of the Adobe Creek drainage channel. The walkway connects 
Miller Avenue to a bridge that spans the Creek at Wilkie Way. The 
walkway is supported on reinforced concrete caissons and reinforced 
concrete cap beams. Wood stringers, k x 12 inch (0.1 x 0.3M) on top 
of the cap beams support the 3x8 inch (0.1 x 0.2M) wood decking. A 
five foot (1.5M) high steel pipe fence with wire mesh is provided at 
the outside edge. A six foot (1.8M) high wood board fence is provided 
at the inside edge adjacent to the residential property that abuts the 
creek. 



193 



The bridge spanning Adobe Creek is constructed of 11 x 45 inch 
(0.3 x 1.1 M) "glu lam" beams supported on reinforced concrete caissons 
and abutments at each end. Its length is 52 feet (15. 8M). The cross 
bracing is one-half inch (12.2MM) diameter steel rod and the struts are 
four inch diameter galvanized pipe. Eight feet (2.4M) of clearance is 
provided between the ins ides of the glu lams. The decking is 4 x 8 inch 
(0.1 x 0.2M) lumber. Steel rods and wire mesh make up the pedestrian 
railings on each side that is fastened to the top of the glu lams. The 
total height of the railings above the decking is five feet (1.5M). See 
Figure 33 for a series of photographs taken at the site. 

Construction Cost 

The cost of construction in 1974-1975 was approximately $82,400 and 
the cost of various items are listed in Table 15. 



Table 15. Summary of Construction Cost 
Palo Alto, California Bridge 



1 tern 


Description 




Quant i 


<7 


Unit 




Price 


Total 


1 


Clearing and Grubbing 




Lump S 


urn 


L.S. 




L.S. 


$ 500.00 


2 


Asphalt Path Construction 




376 




Sq. 


Ft. 


$ 1.30 


488.80 


3 


Concrete Pier Construction 




170 




Lin. 


Ft. 


A3. 00 


7,650.00 


4 


Concrete Construction 




10 




CY 




195.00 


3,950.00 


5 


Structural Steel 




Lump S 


urn 


L.S. 




L.S. 


1 ,830.00 


6 


Wood Construction 




15 




HBFM 




960.00 


14,400.00 


7 


Gl ued- Lamina ted Beams 




2 




Each 




4,000.00 


8,000.00 


8 


Wood Handrai 1 




111 




Lin. 


Ft. 


4.80 


1 ,305.60 


9 


Fence Construction Chain Link 




85 




Lin. 


Ft. 


6.00 


510.00 


10 


Fence Construction Welded Wire 


Fabric 


272 




Lin. 


Ft. 


8.00 


2,176.00 


11 


Fence Construction Steel Rod Balusters 


123 




Lin. 


Ft. 


29.00 


3,567.00 


12 


Redwood Boards 




260 




Lin. 


Ft. 


8.05 


2,093.00 


13 


5-Inch Electrical Ducts 




720 




Lin. 


Ft. 


21.00 


15,120.00 


14 


3-Inch Electrical Ducts 




690 




Lin. 


Ft. 


12.00 


8,349.00 


15 


2-Inch Electrical Ducts 




350 




Lin. 


Ft. 


8.05 


2,817.50 


16 


1-Inch Electrical Ducts 




380 




Lin. 


Ft. 


6.47 


2,438.60 


17 


Electrical Boxes 




2 




Each 




1,000.00 


2,000.00 


18 


Lights 




10 




Each 




72.00 


720.00 


19 


Non-Skid Finish 




2,700 




Sq. 


: t. 


0.35 


945.00 


20 


Painting Complete 




Lump S 


urn 


L.S. 




L.S. 


3,399.00 


21 


Removable Steel Posts 
TOTAL BID 




2 




Each 




56.00 


112.00 
$82,391.50 


NOTE 


: To convert to metric: Feet > 


0.3048 = 


Metres 


; Sq. Ft. 


X 


0.0929 - Sq. Metres 



194 




Figure 33- JAMES A. HAWKINSON PEDESTRIAN-BICYCLE BRIDGE 
Palo Al to, Cal ifornia 

195 



SUNNYVALE, CALIFORNIA 

The pedestrian and bicycle overcrossing of Route 101 in Sunnyvale, 
California, was selected as one of the site evaluation studies because 
it represents a new, exclusively non-motorized facility with examples 
of the latest treatment to facilitate handicapped access. The site is 
shown in the photographs, Figure 3^. 

Background 

U.S. Highway 101, a six lane freeway, divides the City of Sunnyvale 
into two parts. The residents of the Lakewood Village Subdivision in 
the northeastern part of Sunnyvale were separated from various facilities 
south of Route 101, including the high school, shopping center, library, 
city hall, and community center. A particular problem was insufficient 
access for bicyclists and pedestrians. 

It proved difficult to find an acceptable location for construction 
of some type of crossing. Public support was in favor of a crossing 
facility, but residents near the freeway did not want it located near 
their homes. The compromise location necessitated acquisition of two 
duplexes and a vacant lot. The City, in conjunction with the State, 
jointly financed construction of a pedestrian and bicycle overcrossing 
in the vicinity of Ahwanee Avenue in Sunnyvale. 

Structure 

The Ahwanee Avenue Pedestrian Overcrossing main structure is 393 
feet (119.8M) in length and is constructed of cast-in-place prestressed 
concrete girders supported on reinforced concrete pile bents and abut- 
ments. There is 8 feet (2.*tM) of clear space between the curbs on the 
span, and an 8 foot (2.*tM) high chain link fence on each side of the 
main span. The approaches are supported on file and follow curvilinear 
paths to the ground level. Pipe pedestrian handrails are provided on 
the approaches. When the design was well advanced, the approach ramps, 
17^ and 205 feet respectively, were lengthened to lower their maximum 
slope to 8.33 percent specifically to accommodate the handicapped. 
Special rest areas were also designed into the project. 

Construction Cost 

The Ahwanee bicycle/pedestrian overcrossing cost approximately 
$316,000 to construct in 1977. The facility was completed within an 
eight month period. Approximate construction quantities are listed 
in Table 16. 



196 



Precast Pedestrian 
overcross ing 
spanning freeway 




Level rest area 
adjacent to 
approach ramp 



Figure Ik. AHWANEE PEDESTRIAN OVERCROSSING OF ROUTE 101 
Sunnyvale, California 



197 



Table 16. Estimated Construction Quantities- 
Sunnyvale, California Bridge 



1 tern 


Quantity 


Vision Screen 


3,160 Sq. Ft. 


Temporary Railing (Type K) 


380 LF 


Furnish Piling (Class 45-2) 


400 LF 


Furnish Piling (Class 70) 


1,100 LF 


Drive Pile (Class 45) 


6 EA 


Drive Pile (Class 70) 


18 EA 


Prestressing Cast- In-Place Concrete 


Lump Sum 


Waters top 


24 LF 


Joint Seal (Type B-MR 1-1/2") 


24 LF 


Chain Link Railing (Type 7L) 


1,114 LF 


Pipe Handrailing (Post Type) 


506 LF 


FINAL PAY QUANTITIES 




Structure Excavation (Bridge) 


275 CY 


Structure Backfill (Bridge) 


165 CY 


Structural Concrete, Bridge Footing 


60 CY 


Structure Concrete (Bridge) 


420 CY 


Bar Reinforcing Steel (Bridge) 


78,000 LB 


NOTE: To convert to metric: Feet x 0.3048 = 


= Metres;- 


Sq. Ft. x 0.0929 = Sq. Metres 





EUGENE, OREGON 

One undercrossing and one overcrossing were selected in Eugene, 
Oregon for detailed study. In addition, supplemental information was 
gathered concerning two major bicycle/pedestrian bridges spanning the 
Willamette River. The extensive bikeway/pedestrian path system along 
the Willamette River including the river crossings and the north and 
south bank trails lent itself to this type of expanded analysis. 

The bicycle and pedestrian undercrossing of the Southern Pacific 
Railroad adjacent to the University of Oregon was selected as one of the 
two structures to be reviewed in Eugene, Oregon. The undercrossing 
represents an important early link in the pathway system which now 
extends several miles along both sides of the Willamette River. 

The newly constructed ramp serving bicycle and pedestrian access 
from the Ferry Street bridge to the north bank pathway along the 
Willamette River was the second structure selected for detailed review 
because it represents an innovative retrofit treatment designed to 
facilitate bicycle and pedestrian travel between the bridge and the 
pathway beneath. 



198 



Undercrossing Background 

The City of Eugene, Oregon, is an active bicycling and pedestrian 
community, due largely to the University of Oregon campus in the City. 
The Willamette River which flows through the City is a major barrier 
to bicycle circulation. In addition, the university stadium is located 
across the river from the campus. The construction of the Autzen Bridge 
for bicycles and pedestrians over the Willamette River in 1970 removed 
an absolute barrier to direct travel between the University of Oregon 
campus and Autzen Stadium. However, the main line of the Southern 
Pacific Railroad parallels the river at this point, and there was no 
formal crossing. Some 20 to 30 trains a day pass this point, at speeds 
up to 40 mph (64.4KPH). 

To allow access to the stadium during events, a crossing was 
installed and a flagman provided to control the crowds. When no event 
was in progress, the crossing was closed by locked gates. People, however, 
crossed illegally; cutting holes in the railroad fences. 

Undercrossing Structure 

Three-way discussions to resolve the problem were initiated between 
the University of Oregon, Lane County, and Southern Pacific. Plans were 
developed for a corrugated metal arch underpass, but soils tests determined 
that this solution was not feasible. Southern Pacific agreed to install 
a standard prestressed concrete bridge unit, using its own bridge crew, 
with the University and Lane County funding the project. 

The bridge consists of precast prestressed concrete box girders, and is 
17 feet (5-2M) wide and 30 feet (9-1M) in length. The abutments are 
reinforced concrete. A 12 foot (3«7M) wide asphalt concrete path passes 
under the bridge on modest approach grades. The clearance above the 
bicycle and pedestrian path is 10 feet (3-1M). See Figure 35- 

Undercrossing Construction Cost 

The construction cost to create an undercrossing of the SPRR tracks 
was approximately $40,000 when it was built in 1973. Construction of 
the structure was completed within four weeks (detail quantities were not 
available for this project). 

Overcrossing Improvement Background 

One of the major findings of the Bikeway Master Plan Study in 1974 was 
that the existing highway bridges over the Willamette River were generally 
unsuitable for both bicyclist and pedestrian use. One such bridge was 
the Ferry Street Bridge. 

The Ferry Street Bridge carries four traffic lanes on a 48 foot 
(14.6M) roadway, flanked by two 5 foot (1.5M) sidewalks. The average 
daily traffic on the bridge is some 40,000 vehicles. The bridge is the 

199 




S.P.R.R. Under- 
crossing providing 
1 inkage between 
the University of 
Oregon and the 
Autzen bridge 




Figure 35. UNDERCROSSING OF SOUTHERN PACIFIC RAILROAD 
Eugene, Oregon 



200 



major route for bicyclists from North Eugene to downtown. Bicyclists 
typically use both sidewalks in both directions, sharing the space with 
a few pedestrians. The structure is some 800 feet (243. 8M) long. Over 
the kkO foot (13^M) main span, the sidewalks are 5 feet (1.5M) wide, with 
barriers on both sides. On the bridge approach spans, the sidewalks are 
the same width but have no barrier on the traffic side. 

The layout and use of the Ferry Street Bridge exhibited several 
deficiencies of varying concern to cyclists and pedestrian: 

On both sides of the roadway the south approach pathways joined 
the sidewalks at right angles, requiring cyclists to make this 
turn in a space of five feet (1.5M). 

The unprotected sidewalks on the approach spans were inadequate for 
two-way bike traffic, or mixed bicycle and pedestrian traffic. 
There was no designated or convenient route connecting the bridge 
with the North Bank Bike Path that ran adjacent to the river. 

Overcrossing Improvement Structure 

Proposals were made as part of the Bikeway Master Plan to remove 
the most serious deficiencies. The proposals were that a new access 
ramp be constructed on the north end of the structure, connecting the 
east side sidewalk approach with the North Bank Bike Path, that traffic 
barriers be installed adjacent to all the approach sidewalks, and that the 
approach sidewalk on the northeast be widened to 10 feet (3.1M) from the 
existing 5 feet (1.5M). The east sidewalk on the structure and approaches 
would be used by bicyclists only. See Figures 36 and 37- 

Construction of the recommended improvements started in 1976. The 
access ramp is 190 feet (57«9M) in length and is constructed in four 
spans of precast prestressed double tee beams supported on precast columns. 
The ramp grade is 8 percent, and there is a minimum of 10 feet 9 inches 
(3-3M) clear between the railings. The railings are k feet (1.2M) in 
height, and made of rectangular tubular steel. Cross slopes are a maximum 
of k percent, with level rest areas provided at the two central column bents 

The northeast sidewalk approach was widened by canti levering an 
additional 5 foot (1.5M) section outside of the existing sidewalk. The 
cantilevered section is 250 feet (76. 2M) in length, and provides a clear 
width of 10 feet (3.1M) between the new k foot (1.2M) high rectangular tu- 
bular steel outside pedestrian rail and the "New Jersey" type traffic 
barrier with handrail on the inside. The cantilevered section is supported 
by welded and bolted structural steel attached to the reinforced concrete 
beams and columns along the outside edge of the approach structure. 

Approximately 500 L.F. (152. *tM) of the "New Jersey" traffic barrier 
was erected, in addition to that adjacent to the cantilevered sidewalk 
section, on the other approach walks. 



20 




New ramp 
connect ing 
bridge approach 
to ramp 




View of ramp showing level rest area 
partial ly up the grade 



intersection of 
new ramp with 
original bridge 
approach 



Figure 36. RETROFITTED RAMP, FERRY STEET BRIDGE 
Eugene, Oregon 



202 




Narrow unprotected sidewalk 
before improvement 



Widened sidewalk with protected barrier 
after improvement 




Cant i levered 
supports for 
widened sidewalk 
after condition 



Figure 37. 



FERRY STREET BRIDGE 
Eugene, Oregon 



203 



In addition to the completed approach widening, a preliminary study 
and design for widening the east sidewalk on the truss main span of the 
Ferry Street Bridges has been completed. Additional sidewalk width would 
be obtained by canti levering four feet (1.2M) of sidewalk outside of the 
existing walkway in a manner similar to the approach section. 

Overcrossing Improvement Construction Cost 

The construction cost to complete the retrofitted access ramp and 
sidewalk widening on Ferry Street Bridge was $171,000 in 1977- Of this, 
$120,000 was to construct the new access ramp and $51,000 to widen side- 
walk and to erect New Jersey type traffic barriers. Completion of the 
entire project took five months. 

Preliminary cost estimates prepared in 1977 for widening the Ferry 
Street bridge truss spans to create a wider sidewalk on the east side of 
the bridges are shown in Table 17. 



Table 17- Preliminary Cost Estimates- 
Eugene, Oregon Bridge 
Sidewalk Widening 



Preliminary Cost Estimate 


Quantity 


Total 


Mobi 1 ization 




$ 3,500 


Traffic Control 




1,500 


Staging at Panel Points 


18 Each @ $600 


10,800 


Remove Rail and Curb 


444 L.F. § $8 


3,552 


Drill Anchorage Holes in SW 


54 Each @ $10 


540 


Grout in Anchorages 


18 Each @ $30 


540 


Field Drill Fascia Channel 


216 Each § $3.50 


756 


Structural Steel in Place 


27,000 Lbs. g $1.10 


29,700 


Install Strut Brackets 


18 Each @ $100 


1,800 


Paint All Steel 


All 


2,000 


Class "A" Concrete 


20 C.Y. @ $250 


5,000 


Reinforcing Steel 


3,000 Lbs. § $0.50 


1,500 


Metal Railing 


444 L.F. @ $30 


13,320 
$74,508 




Add 10% Contingencies 


7,492 
"$82,000 


Engineering Fees 


Design @ 7-1/2% 


6,150 




Field Supervision @ 5-1/2% 


4,500 


NOTE: To convert to metric: 


Total Cost 
Feet x 0.3048 = Metres; 


$92,650 




Pounds x 0.4536 = Kil 


ograms 





204 



Supplemental Eugene, Oregon Inspections 

In addition to the case studies conducted at the Southern Pacific 
Railroad undercross ing and at the retrofitted ramp/Ferry Street Bridge 
complex, the study team also briefly inspected other elements of the north 
and south bank pathway system. The following information pertains to 
the Autzen Bridge and new Greenway Bike Bridge. See photographs, Figure 38. 

Autzen Bridge. The Willamette River which flows through the City is 
a major barrier to bicycle circulation. In addition, Autzen Stadium is 
located across the river from the University of Oregon campus. The only 
crossings were two highway bridges, both located some distance from the 
campus on each side, and both largely unsuitable for bicycle and pedestrian 
traffic because of safety deficiencies. 

A bridge was proposed near the campus to carry utilities across 
the river. The community coordinated with the utility company to 
construct a combination pedestrian/bicycle bridge over the river, with 
the utility pipes slung below the bridge deck. The bridge is 667 feet 
(203. 3M) in length and the clear railing to railing width is 12 feet 
(3.7M). The bridge consists of two side by side precast prestressed 
bulb tee beams. The four center spans are each 130 feet (39. 6M) in 
length, and the end spans are 66 and 82 feet (20.1 and 25M) respectively. 
Piers and abutments are reinforced concrete. The concrete curbs with 
aluminum tubing and wood railing are 3.5 feet (1.1 M) high. At each of 
the piers, the bridge deck is widened to accommodate a bench for resting 
and space to enjoy the views. 

Total cost was $186,000 in 1970 and it was completed in a five month 
period. Costs were shared by the Eugene Water and Electric Board; University 
of Oregon Athletic Department and Lane County. Construction quantities 
were not available for this project. 

Greenway Bicycle/Pedestrian Bridge. A recommendation was made in 
the Eugene Bikeway Master Plan to construct a bicycle/pedestrian bridge 
over the Willamette River at the point of greatest utility to the bike 
route network. Consideration was given to three different bridge designs: 
a four span prestressed girder bridge, a cable-stayed bridge, and a 
suspension bridge. Visual impact was an important consideration since 
the bridge would be visible from both banks of the river over a long 
distance. Other important considerations were the clearance requirements 
for navigation purposes and the cost of the structure. 

The design selected was the four span prestressed girder bridge, with 
its low cost being a major factor in its selection. The Valley River 
Bicycle/Pedestrian Bridge is 528 feet (160.9M) in length and has a clear 
width on its deck of 13 feet k inches (4M) from inside of rail to inside 
of rail. The four 132 foot (*t0.2M) spans are supported on reinforced 
concrete piers and abutments. The deck spans consist of two side by 
side bulb tee prestressed beams. The bridge deck is widened at each 
pier to accommodate benches for sitting and resting. The wooden handrails 
are 3-5 feet (MM) high. 

205 




Greenway bicycle pedestrian bridge over the Willamette river 




Runners on the 
Autzen bicycle 
pedestrian 
bridge over the 
Wi 1 lamette river 



Figure 38. SUPPLEMENTAL INSPECTION SITES 
Eugene, Oregon 

206 



Federal Bicycle Demonstration Project funds (FHWA) were obtained in 
1977 for the project, and the bridge was dedicated in February, 1978. 
Total construction cost for the project was $277,500. Construction 
quantities are listed in Table 18. 



Table 18. Construction Quantities- 
Eugene, Oregon Bicycle/Pedestrian Bridge 



1 tern 


Un 


it 


Quantity 


Mobil ization 


All 




All 


Embankment in Place 


Cu. 


Yd. 


1430 


l"-0 Aggregate Base 


Cu. 


Yd. 


35 


Class "C" Asphalt Concrete 


Ton 




20 


Bark Mulch 


Unit 




1.5 


Bridge No. 1631 6 








Alternate "A" 








Shoring, Cribbing, etc. 


All 




All 


Structure Excavation 


Cu. 


Yd. 


730 


Special Backfill 


Cu. 


Yd. 


130 


Furnish Pile Driving Equipment 


All 




All 


Furnish 14-inch Prestressed Concrete Piling 


Lin. 


Ft. 


2018 


Drive Prestress Concrete Piles 


Lin. 


Ft. 


1824 


Structural Concrete, Class 3300 


All 




All 


Structural Concrete, Class 4000 


All 




All 


1 30 ' /l 35 ' Bulb Tee Prestressed Beams 


Each 




8 


Reinforcement 


All 




All 


Prestressing Steel 


All 




All 


Structural Steel 


All 




All 


Pedestrian Rail 


All 




All 


Pedestrian Benches 


Each 




6 


1-1/2 inch Electrical Conduit 


Lin. 


Ft. 


675 


Loose Riprap, Class 100 


Cu. 


Yd. 


575 


NOTE: To convert to metric: Feet x 0.3048 = 


Metres; 




Pounds x 0.4536 = Kilograms 









207 



HAMPTON, NEW HAMPSHIRE 

The bridge carrying U.S. Route 1 over the B&M Railroad (Bridge 
1 63/ 1 84) in Hampton, New Hampshire was selected as one of the site 
evaluation studies. The bridge represents an example of a retrofit 
treatment. 

Background 

Originally built in 1936, the bridge is 120 feet (36. 6M) long and 
has a curb-to-curb width of 34 feet (10. 4M) . The original construction 
provided only a narrow 1 foot 8 inches (0.5M) catwalk on the structure 
and a 2 feet 6 inches (0.8M) setback from the curb to the highway rail 
on the approaches. See photographs, Figure 39. 

Retrofit Structure 

The 1977 reconstruction provides a separation of pedestrians from 
the vehicles, and a wider 4 foot (1.2M) walkway on both the structure 
and the approaches. The existing wood guard rails on the approaches 
were removed and replaced with steel beam guardrails set closer to the 
curb. The slope area outside the new guardrails was widened to accommo- 
date a 4 foot (1.2M) asphalt concrete sidewalk A 4 foot (1.2M) wide 
pedestrian walkway is canti levered off of the outside of the overhead 
structure. The walkway is constructed of steel angles and beams fastened 
by gusset plastes to the outside of the existing steel beam structure. 

Construction Cost 

The total construction cost in 1977 to retrofit the bridge with 
canti levered walkways and to develop the pathway approaches was 
$72,000; of this about $32,000 were required for the approach sidewalks 
and $40,000 for the bridge modifications. Itemized construction quantities 
were not available for this project. 

ROUTE 183, RANDOLPH ROAD, MARYLAND 

The new culvert carrying Paint Branch Creek under Randolph Road 
(Maryland Route 1 83) was selected as one of the site evaluation studies. 
Of special interest was the creation of a raised walkway in one of the 
culvert cells to facilitate trail users crossing under Randolph Road. 

Background 

Maryland Route I83, Randolph Road, was proposed for relocation in 
1 976- 1 977 • The newly constructed road passed through a park area, 
dividing it into two parts. The road was considered dangerous to cross 
at grade level, and some provision was necessary so that hikers and 
bikers could more safely move from one part of the park to the other. 



208 



New wa 1 kway" 
cant i levered 
onto existing 
bridge 




New pathway 
bui 1 t paral lei 
to roadway 



Figure 39. RETROFITTED BRIDGE 

Hampton, New Hampshire 



209 



A box culvert drainage structure was part of the reconstruction of 
Randolph Road. A decision was made to modify one of the cells in the 
multi-cell culvert for the purpose of accommodating the movement of 
bicyclists and hikers. 

Structure 

The box culvert consists of four cells each 18 feet (5-5M) wide 
and 11 feet (3-^M) high, and is constructed of reinforced concrete. 
The length of the structure from headwall to headwal 1 is 168 feet (51. 2M) 

In the easterly cell, a concrete slab 8 feet (2.*tM) wide was con- 
structed next to the outer wall 3 feet 6 inches (1.1 M) above the culvert 
invert. Overhead clearance of 7 feet 6 inches (2.3M) is thus available. 
A 3 foot (0.9M) high pedestrian handrailing constructed of pipe is 
provided at the outside edge of the slab. See. photographs, Figure 40. 

The slab is sufficiently above the culvert floor that it is above 
water except under extreme flood conditions. The design also provides 
for lighting to illuminate the walkway within the culvert. 

Construction Cost 



The total construction cost of the quadruple 11 foot x 18 foot 
reinforced concrete box culvert, of which the raised sidewalk was a 
part, amounted to some $150,000. The construction took place in 
1976-1977- The estimated construction quantities are listed in Table 19 



AUSTIN, TEXAS 

The interchange of 5th and 6th Streets with MoPack Boulevard in 
Austin, Texas, was selected as one of the site evaluation studies. 
The interchange is a complex network of one-way streets and ramps 
through which special off-street facilities have been constructed to 
accommodate bicycle and pedestrian travel. The interchange contains 
an extensive pathway system together with exclusive bicycle/pedestrian 
overpasses and underpasses. 

Background 

The bicycle is increasingly used as a means of transportation 
in the City of Austin. The City's Comprehensive Plan establishes a 
policy of providing bicycle facilities where appropriate, and there 
is a City Bikeway System Plan. 

One hazardous area frequently traversed by cyclists was the 
interchange of MoPack Boulevard, a six lane controlled access north- 
south facility, and four east-west arterial streets. Three of those 
streets, Lake Austin Boulevard and West 5th and 6th Streets, are primary 



210 






Maryland 
Route 183 
cross ing 
over culvert 




Pathway to be 
extended in 
the future 



Figure *t0 . BOX CULVERT UNDERCROSS ING 
Maryland Route 1 83 



211 



Table 19. Estimated Construction Quantities- 
Maryland Route 183 Box Culvert 







Method of 


Estimated 


Category 


Item 


Measurement 


Quant i ty 


Grading 


Class 5 Excavation 




CY 


2250 


Drainage 


Selected Backfill Using #G 










Aggregate 




CY 


250 




Selected Backfill Using Crushe 


r 








Run or Type 2 Sub-base 




CY 


250 




Slope Protection Using 6 In. 










Mix No. 1 Concrete 




SY 


450 




Concrete Cut Off Wall 




CY 


30 


Structures 


Class #3 Excavation for Structi 


jres 


CY 


1900 




Class §k Excavation 




CY 


1300 




Subfoundation Concrete 




CY 


20 




Quadruple 18. Ft. x 11.0 Ft. 










Reinforced Concrete Box Culvert 








at Sta. 79+ 




LS 


LS 




Contingent Concrete for Box 










Culvert 




CY 


10 




Galvanized Pipe Railing 




LF 


230 




Electric Lighting System for 










Hiker-Biker Underpass 




LS 


LS 


Landscaping 


Sol id Sodding 




SY 


80 


NOTE: To convert to Metric, multiply feet x 


.3048 







routes for cyclists. To the west of the interchange, Lake Austin 
Boulevard has two lanes in each direction. It divides into two 2^-foot 
roadways inside the interchange and these transition into 5th and 6th 
Streets, which continue as a one-way pair to the east of the interchange. 
The Lake Austin Boulevard-5th/6th Street connections have potential for 
increased bicycling activity. There are four residential areas for 
University of Texas at Austin married students located near the inter- 
change, housing 2,800 persons. Many of these residents travel to the 
main campus daily along this primary route. In addition, Austin High 
School is located between the interchange and Town Lake. The lake, roadway 
connections and an adjacent railroad mainline make access to the school 
site very difficult for non-motorized users. 

212 



Project 

The City of Austin received a Federal grant through the Bikeway 
Demonstration Program to mitigate the barriers to non-motorized travel 
created by the freeway interchange. The project was completed in 1977 
and provides alternative pathways through the interchange by modifying 
existing structures, construction of pathways, and erection of two 
bicycle/pedestrian bridges. See photographs, Figures *»1 , k2 and k?>. 

Construction Cost 

The cost to construct the two bicycle/pedestrian bridges and 
pathway through the interchange associated with the 5th and 6th Street 
bikeways amounted to some $210,000 in 1977. Construction duration took 
approximately three months, although lighting along the 5th Street 
pathway was still being completed in the fall of 1978. An itemized cost 
estimate is shown in Table 20. 



213 



Table 20. Estimated Construction Quantities- 
Austin, Texas Bikeways 



1. 


Eastbound Bikeway (5th Street) 
















Est. 


Unit 


Est. Line 










L.F. 


Cost 


Cost 




Bridge Rework 






205' 


$ 45. 


$ 9,225 




Bridge Work 






180' 


275. 


49,500 




Retaining Wall Work 






230' 


60. 


13,800 




Path Work 






945' 


4. 


3,780 




Path w/Fill 






350' 


6. 


2,100 




Path w/Cut 






130' 


8. 
1. SUBTOTAL 


1,040 
$ 79,445 


11. 


Westbound Bikeway (6th Street) 










Protected Lane 






760' 


$ 2.50 


1,900 




Bridge Work 






150' 


275- 


41,250 




Bridge Rework 






205' 


45. 


9,225 




Retaining Wal 1 Work 






115' 


60. 


6,900 




Path Work 






795' 


4. 
Subtotal 

1 1 . SUBTOTAL 


3,180 

$ 62,445 

15,000 

77,445 


111. 


Project Total 














Subtotal 


(1 + 


11) 






$156,900 




Mi seel laneous 


Lightii 


ig 




15,000 




Project 


Subtotal 






171,900 




20% Engi 


neering + Contingencies 


34,380 




Project 


Total 








206,280 




Evaluation + 


Report 






3,720 




TOTAL 










$210,000 


Federal Share (80%) = $168,000 










Local 


Match (20%) = $ 42 


,000 










NOTE: 


To convert to metri 


c: Feet x 


.3048 


= Metres 





214 



Signing and 
s i ting of 
bikeway bridge 
in interchange 





Bikeway bridge 
close-up 





Formal i zed 
off pathway 
rest area 
along a grade 



Figure 41. FIFTH STREET BIKEWAY 
Austin, Texas 



215 



Original sidewalk 
and new bikeway 
crossing under 
ra i 1 road 




Bikeway bridge 
close-up. Note 
handrai 1 , fenc- 
ing and wood 
post wing wal Is 



Figure kl. SIXTH STREET BIKEWAY 
Austin, Texas 



2)6 



Pathway ut i 1 izes 
cul vert eel 1 with 
a raised floor 
to cross under 
interchange ramp 



Bike/Pedestrian 
bridge connect 
pathway to 
culvert underpass 




wmm 





One of several 
3 foot (0.9m) long 
on-path level rest 
areas ascending 
a long hill 



Figure 43. NORTH SOUTH B I KEWAY 
Austin, Texas 

217 



•U.S. GOVERNMENT PRINTING OFFICE: 1981-0-725-501/1080 






o-a 



FEDERALLY COORDINATED PROGRAM (FCP) OF HIGHWAY 
RESEARCH AND DEVELOPMENT 



The Offices of Research and Development (R&D) of 
the Federal Highway Administration (FHWA) are 
responsible for a broad program of staff and contract 
research and development and a Federal-aid 
program, conducted by or through the State highway 
transportation agencies, that includes the Highway 
Planning and Research (HP&R) program and the 
National Cooperative Highway Research Program 
(NCHRP) managed by the Transportation Research 
Board. The FCP is a carefully selected group of proj- 
ects that uses research and development resources to 
obtain timely solutions to urgent national highway 
engineering problems.* 

The diagonal double stripe on the cover of this report 
represents a highway and is color-coded to identify 
the FCP category that the report falls under. A red 
stripe is used for category 1, dark blue for category 2, 
light blue for category 3, brown for category 4, gray 
for category 5, green for categories 6 and 7, and an 
orange stripe identifies category 0. 

FCP Category Descriptions 

1. Improved Highway Design and Operation 
for Safety 

Safety R&D addresses problems associated with 
the responsibilities of the FHWA under the 
Highway Safety Act and includes investigation of 
appropriate design standards, roadside hardware, 
signing, and physical and scientific data for the 
formulation of improved safety regulations. 

2. Reduction of Traffic Congestion, and 
Improved Operational Efficiency 

Traffic R&D is concerned with increasing the 
operational efficiency of existing highways by 
advancing technology, by improving designs for 
existing as well as new facilities, and by balancing 
the demand-capacity relationship through traffic 
management techniques such as bus and carpool 
preferential treatment, motorist information, and 
rerouting of traffic. 

3. Environmental Considerations in Highway 
Design, Location, Construction, and Opera- 
tion 

Environmental R&D is directed toward identify- 
ing and evaluating highway elements that affect 



• The complete seven-volume official statement of the FCP is available from 
the National Technical Information Service, Springfield, Va. 22161. Single 
copies of the introductory volume are available without charge from Program 
Analysis (HRD-3), Offices of Research and Development, Federal Highway 
Administration, Washington, D.C. 20590. 



the quality of the human environment. The goals 
are reduction of adverse highway and traffic 
impacts, and protection and enhancement of the 
environment. 

4. Improved Materials Utilization and 
Durability 

Materials R&D is concerned with expanding the 
knowledge and technology of materials properties, 
using available natural materials, improving struc- 
tural foundation materials, recycling highway 
materials, converting industrial wastes into useful 
highway products, developing extender or 
substitute materials for those in short supply, and 
developing more rapid and reliable testing 
procedures. The goals are lower highway con- 
struction costs and extended maintenance-free 
operation. 

5. Improved Design to Reduce Costs, Extend 
Life Expectancy, and Insure Structural 
Safety 

Structural R&D is concerned with furthering the 
latest technological advances in structural and 
hydraulic designs, fabrication processes, and 
construction techniques to provide safe, efficient 
highways at reasonable costs. 

6. Improved Technology for Highway 
Construction 

This category is concerned with the research, 
development, and implementation of highway 
construction technology to increase productivity, 
reduce energy consumption, conserve dwindling 
resources, and reduce costs while improving the 
quality and methods of construction. 

7. Improved Technology for Highway 
Maintenance 

This category addresses problems in preserving 
the Nation's highways and includes activities in 
physical maintenance, traffic services, manage- 
ment, and equipment. The goal is to maximize 
operational efficiency and safety to the traveling 
public while conserving resources. 

0. Other New Studies 

This category, not included in the seven-volume 
official statement of the FCP, is concerned with 
HP&R and NCHRP studies not specifically related 
to FCP projects. These studies involve R&D 
support of other FHWA program office research. 



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